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


import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.StringTokenizer;

public class C2 {

    static BufferedReader in;
    static StringTokenizer st;
    static PrintWriter out;

    static String next() throws IOException {
        while (st == null || !st.hasMoreTokens()) {
            st = new StringTokenizer(in.readLine());
        }
        return st.nextToken();
    }

    static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }

    public static void main(String[] args) throws IOException {
        in = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
                System.out)));
        long[] a = { 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.parseLong("4444444444") };
        long l = nextInt();
        long templ = l;
        long r = nextInt();
        long sum = 0;
        for (int i = 0; i < a.length; i++) {
            if (l <= a[i] && r >= a[i]) {
                sum += (long) (a[i] - l) * a[i];
                l = a[i];
            }
        }
        for (int i = 0; i < a.length; i++) {
            if (l < a[i]) {
                sum += (long) (r - l) * a[i];
                break;
            }
        }
        for (int i = 0; i < a.length; i++) {
            if (templ <= a[i]) {
                sum += a[i];
                break;
            }
        }
        out.print(sum);
        out.close();
    }
}