Petya loves lucky numbers. Everybody knows that lucky numbers are positive integers whose decimal representation contains only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not.

Let next(x) be the minimum lucky number which is larger than or equals x. Petya is interested what is the value of the expression next(l) + next(l + 1) + ... + next(r - 1) + next(r). Help him solve this problem.

Input

The single line contains two integers l and r (1 ≤ l ≤ r ≤ 109) — the left and right interval limits.

Output

In the single line print the only number — the sum next(l) + next(l + 1) + ... + next(r - 1) + next(r).

Please do not use the %lld specificator to read or write 64-bit integers in C++. It is preferred to use the cin, cout streams or the %I64d specificator.

Examples

Input

2 7


Output

33


Input

7 7


Output

7

Note

In the first sample: next(2) + next(3) + next(4) + next(5) + next(6) + next(7) = 4 + 4 + 4 + 7 + 7 + 7 = 33

In the second sample: next(7) = 7
#include <bits/stdc++.h>
using namespace std;
int n;
long long a[100001] = {4,         7,         44,
                       47,        74,        77,
                       444,       447,       474,
                       477,       744,       747,
                       774,       777,       4444,
                       4447,      4474,      4477,
                       4744,      4747,      4774,
                       4777,      7444,      7447,
                       7474,      7477,      7744,
                       7747,      7774,      7777,
                       44444,     44447,     44474,
                       44477,     44744,     44747,
                       44774,     44777,     47444,
                       47447,     47474,     47477,
                       47744,     47747,     47774,
                       47777,     74444,     74447,
                       74474,     74477,     74744,
                       74747,     74774,     74777,
                       77444,     77447,     77474,
                       77477,     77744,     77747,
                       77774,     77777,     444444,
                       444447,    444474,    444477,
                       444744,    444747,    444774,
                       444777,    447444,    447447,
                       447474,    447477,    447744,
                       447747,    447774,    447777,
                       474444,    474447,    474474,
                       474477,    474744,    474747,
                       474774,    474777,    477444,
                       477447,    477474,    477477,
                       477744,    477747,    477774,
                       477777,    744444,    744447,
                       744474,    744477,    744744,
                       744747,    744774,    744777,
                       747444,    747447,    747474,
                       747477,    747744,    747747,
                       747774,    747777,    774444,
                       774447,    774474,    774477,
                       774744,    774747,    774774,
                       774777,    777444,    777447,
                       777474,    777477,    777744,
                       777747,    777774,    777777,
                       4444444,   4444447,   4444474,
                       4444477,   4444744,   4444747,
                       4444774,   4444777,   4447444,
                       4447447,   4447474,   4447477,
                       4447744,   4447747,   4447774,
                       4447777,   4474444,   4474447,
                       4474474,   4474477,   4474744,
                       4474747,   4474774,   4474777,
                       4477444,   4477447,   4477474,
                       4477477,   4477744,   4477747,
                       4477774,   4477777,   4744444,
                       4744447,   4744474,   4744477,
                       4744744,   4744747,   4744774,
                       4744777,   4747444,   4747447,
                       4747474,   4747477,   4747744,
                       4747747,   4747774,   4747777,
                       4774444,   4774447,   4774474,
                       4774477,   4774744,   4774747,
                       4774774,   4774777,   4777444,
                       4777447,   4777474,   4777477,
                       4777744,   4777747,   4777774,
                       4777777,   7444444,   7444447,
                       7444474,   7444477,   7444744,
                       7444747,   7444774,   7444777,
                       7447444,   7447447,   7447474,
                       7447477,   7447744,   7447747,
                       7447774,   7447777,   7474444,
                       7474447,   7474474,   7474477,
                       7474744,   7474747,   7474774,
                       7474777,   7477444,   7477447,
                       7477474,   7477477,   7477744,
                       7477747,   7477774,   7477777,
                       7744444,   7744447,   7744474,
                       7744477,   7744744,   7744747,
                       7744774,   7744777,   7747444,
                       7747447,   7747474,   7747477,
                       7747744,   7747747,   7747774,
                       7747777,   7774444,   7774447,
                       7774474,   7774477,   7774744,
                       7774747,   7774774,   7774777,
                       7777444,   7777447,   7777474,
                       7777477,   7777744,   7777747,
                       7777774,   7777777,   44444444,
                       44444447,  44444474,  44444477,
                       44444744,  44444747,  44444774,
                       44444777,  44447444,  44447447,
                       44447474,  44447477,  44447744,
                       44447747,  44447774,  44447777,
                       44474444,  44474447,  44474474,
                       44474477,  44474744,  44474747,
                       44474774,  44474777,  44477444,
                       44477447,  44477474,  44477477,
                       44477744,  44477747,  44477774,
                       44477777,  44744444,  44744447,
                       44744474,  44744477,  44744744,
                       44744747,  44744774,  44744777,
                       44747444,  44747447,  44747474,
                       44747477,  44747744,  44747747,
                       44747774,  44747777,  44774444,
                       44774447,  44774474,  44774477,
                       44774744,  44774747,  44774774,
                       44774777,  44777444,  44777447,
                       44777474,  44777477,  44777744,
                       44777747,  44777774,  44777777,
                       47444444,  47444447,  47444474,
                       47444477,  47444744,  47444747,
                       47444774,  47444777,  47447444,
                       47447447,  47447474,  47447477,
                       47447744,  47447747,  47447774,
                       47447777,  47474444,  47474447,
                       47474474,  47474477,  47474744,
                       47474747,  47474774,  47474777,
                       47477444,  47477447,  47477474,
                       47477477,  47477744,  47477747,
                       47477774,  47477777,  47744444,
                       47744447,  47744474,  47744477,
                       47744744,  47744747,  47744774,
                       47744777,  47747444,  47747447,
                       47747474,  47747477,  47747744,
                       47747747,  47747774,  47747777,
                       47774444,  47774447,  47774474,
                       47774477,  47774744,  47774747,
                       47774774,  47774777,  47777444,
                       47777447,  47777474,  47777477,
                       47777744,  47777747,  47777774,
                       47777777,  74444444,  74444447,
                       74444474,  74444477,  74444744,
                       74444747,  74444774,  74444777,
                       74447444,  74447447,  74447474,
                       74447477,  74447744,  74447747,
                       74447774,  74447777,  74474444,
                       74474447,  74474474,  74474477,
                       74474744,  74474747,  74474774,
                       74474777,  74477444,  74477447,
                       74477474,  74477477,  74477744,
                       74477747,  74477774,  74477777,
                       74744444,  74744447,  74744474,
                       74744477,  74744744,  74744747,
                       74744774,  74744777,  74747444,
                       74747447,  74747474,  74747477,
                       74747744,  74747747,  74747774,
                       74747777,  74774444,  74774447,
                       74774474,  74774477,  74774744,
                       74774747,  74774774,  74774777,
                       74777444,  74777447,  74777474,
                       74777477,  74777744,  74777747,
                       74777774,  74777777,  77444444,
                       77444447,  77444474,  77444477,
                       77444744,  77444747,  77444774,
                       77444777,  77447444,  77447447,
                       77447474,  77447477,  77447744,
                       77447747,  77447774,  77447777,
                       77474444,  77474447,  77474474,
                       77474477,  77474744,  77474747,
                       77474774,  77474777,  77477444,
                       77477447,  77477474,  77477477,
                       77477744,  77477747,  77477774,
                       77477777,  77744444,  77744447,
                       77744474,  77744477,  77744744,
                       77744747,  77744774,  77744777,
                       77747444,  77747447,  77747474,
                       77747477,  77747744,  77747747,
                       77747774,  77747777,  77774444,
                       77774447,  77774474,  77774477,
                       77774744,  77774747,  77774774,
                       77774777,  77777444,  77777447,
                       77777474,  77777477,  77777744,
                       77777747,  77777774,  77777777,
                       444444444, 444444447, 444444474,
                       444444477, 444444744, 444444747,
                       444444774, 444444777, 444447444,
                       444447447, 444447474, 444447477,
                       444447744, 444447747, 444447774,
                       444447777, 444474444, 444474447,
                       444474474, 444474477, 444474744,
                       444474747, 444474774, 444474777,
                       444477444, 444477447, 444477474,
                       444477477, 444477744, 444477747,
                       444477774, 444477777, 444744444,
                       444744447, 444744474, 444744477,
                       444744744, 444744747, 444744774,
                       444744777, 444747444, 444747447,
                       444747474, 444747477, 444747744,
                       444747747, 444747774, 444747777,
                       444774444, 444774447, 444774474,
                       444774477, 444774744, 444774747,
                       444774774, 444774777, 444777444,
                       444777447, 444777474, 444777477,
                       444777744, 444777747, 444777774,
                       444777777, 447444444, 447444447,
                       447444474, 447444477, 447444744,
                       447444747, 447444774, 447444777,
                       447447444, 447447447, 447447474,
                       447447477, 447447744, 447447747,
                       447447774, 447447777, 447474444,
                       447474447, 447474474, 447474477,
                       447474744, 447474747, 447474774,
                       447474777, 447477444, 447477447,
                       447477474, 447477477, 447477744,
                       447477747, 447477774, 447477777,
                       447744444, 447744447, 447744474,
                       447744477, 447744744, 447744747,
                       447744774, 447744777, 447747444,
                       447747447, 447747474, 447747477,
                       447747744, 447747747, 447747774,
                       447747777, 447774444, 447774447,
                       447774474, 447774477, 447774744,
                       447774747, 447774774, 447774777,
                       447777444, 447777447, 447777474,
                       447777477, 447777744, 447777747,
                       447777774, 447777777, 474444444,
                       474444447, 474444474, 474444477,
                       474444744, 474444747, 474444774,
                       474444777, 474447444, 474447447,
                       474447474, 474447477, 474447744,
                       474447747, 474447774, 474447777,
                       474474444, 474474447, 474474474,
                       474474477, 474474744, 474474747,
                       474474774, 474474777, 474477444,
                       474477447, 474477474, 474477477,
                       474477744, 474477747, 474477774,
                       474477777, 474744444, 474744447,
                       474744474, 474744477, 474744744,
                       474744747, 474744774, 474744777,
                       474747444, 474747447, 474747474,
                       474747477, 474747744, 474747747,
                       474747774, 474747777, 474774444,
                       474774447, 474774474, 474774477,
                       474774744, 474774747, 474774774,
                       474774777, 474777444, 474777447,
                       474777474, 474777477, 474777744,
                       474777747, 474777774, 474777777,
                       477444444, 477444447, 477444474,
                       477444477, 477444744, 477444747,
                       477444774, 477444777, 477447444,
                       477447447, 477447474, 477447477,
                       477447744, 477447747, 477447774,
                       477447777, 477474444, 477474447,
                       477474474, 477474477, 477474744,
                       477474747, 477474774, 477474777,
                       477477444, 477477447, 477477474,
                       477477477, 477477744, 477477747,
                       477477774, 477477777, 477744444,
                       477744447, 477744474, 477744477,
                       477744744, 477744747, 477744774,
                       477744777, 477747444, 477747447,
                       477747474, 477747477, 477747744,
                       477747747, 477747774, 477747777,
                       477774444, 477774447, 477774474,
                       477774477, 477774744, 477774747,
                       477774774, 477774777, 477777444,
                       477777447, 477777474, 477777477,
                       477777744, 477777747, 477777774,
                       477777777, 744444444, 744444447,
                       744444474, 744444477, 744444744,
                       744444747, 744444774, 744444777,
                       744447444, 744447447, 744447474,
                       744447477, 744447744, 744447747,
                       744447774, 744447777, 744474444,
                       744474447, 744474474, 744474477,
                       744474744, 744474747, 744474774,
                       744474777, 744477444, 744477447,
                       744477474, 744477477, 744477744,
                       744477747, 744477774, 744477777,
                       744744444, 744744447, 744744474,
                       744744477, 744744744, 744744747,
                       744744774, 744744777, 744747444,
                       744747447, 744747474, 744747477,
                       744747744, 744747747, 744747774,
                       744747777, 744774444, 744774447,
                       744774474, 744774477, 744774744,
                       744774747, 744774774, 744774777,
                       744777444, 744777447, 744777474,
                       744777477, 744777744, 744777747,
                       744777774, 744777777, 747444444,
                       747444447, 747444474, 747444477,
                       747444744, 747444747, 747444774,
                       747444777, 747447444, 747447447,
                       747447474, 747447477, 747447744,
                       747447747, 747447774, 747447777,
                       747474444, 747474447, 747474474,
                       747474477, 747474744, 747474747,
                       747474774, 747474777, 747477444,
                       747477447, 747477474, 747477477,
                       747477744, 747477747, 747477774,
                       747477777, 747744444, 747744447,
                       747744474, 747744477, 747744744,
                       747744747, 747744774, 747744777,
                       747747444, 747747447, 747747474,
                       747747477, 747747744, 747747747,
                       747747774, 747747777, 747774444,
                       747774447, 747774474, 747774477,
                       747774744, 747774747, 747774774,
                       747774777, 747777444, 747777447,
                       747777474, 747777477, 747777744,
                       747777747, 747777774, 747777777,
                       774444444, 774444447, 774444474,
                       774444477, 774444744, 774444747,
                       774444774, 774444777, 774447444,
                       774447447, 774447474, 774447477,
                       774447744, 774447747, 774447774,
                       774447777, 774474444, 774474447,
                       774474474, 774474477, 774474744,
                       774474747, 774474774, 774474777,
                       774477444, 774477447, 774477474,
                       774477477, 774477744, 774477747,
                       774477774, 774477777, 774744444,
                       774744447, 774744474, 774744477,
                       774744744, 774744747, 774744774,
                       774744777, 774747444, 774747447,
                       774747474, 774747477, 774747744,
                       774747747, 774747774, 774747777,
                       774774444, 774774447, 774774474,
                       774774477, 774774744, 774774747,
                       774774774, 774774777, 774777444,
                       774777447, 774777474, 774777477,
                       774777744, 774777747, 774777774,
                       774777777, 777444444, 777444447,
                       777444474, 777444477, 777444744,
                       777444747, 777444774, 777444777,
                       777447444, 777447447, 777447474,
                       777447477, 777447744, 777447747,
                       777447774, 777447777, 777474444,
                       777474447, 777474474, 777474477,
                       777474744, 777474747, 777474774,
                       777474777, 777477444, 777477447,
                       777477474, 777477477, 777477744,
                       777477747, 777477774, 777477777,
                       777744444, 777744447, 777744474,
                       777744477, 777744744, 777744747,
                       777744774, 777744777, 777747444,
                       777747447, 777747474, 777747477,
                       777747744, 777747747, 777747774,
                       777747777, 777774444, 777774447,
                       777774474, 777774477, 777774744,
                       777774747, 777774774, 777774777,
                       777777444, 777777447, 777777474,
                       777777477, 777777744, 777777747,
                       777777774, 777777777, (long long)(4444444444.0)};
int main() {
  long long ans = 0;
  long long l, r;
  scanf("%I64d %I64d\n", &l, &r);
  long long k = l;
  int i = 0;
  while (a[i] < k) i++;
  while (k <= r) {
    if (a[i] <= r)
      ans = (a[i] - k + 1) * a[i] + ans;
    else
      ans = (r - k + 1) * a[i] + ans;
    k = a[i] + 1;
    i++;
  }
  cout << ans;
  fclose(stdin);
  fclose(stdout);
  return 0;
}
