Your security guard friend recently got a new job at a new security company. The company requires him to patrol an area of the city encompassing exactly N city blocks, but they let him choose which blocks. That is, your friend must walk the perimeter of a region whose area is exactly N blocks. Your friend is quite lazy and would like your help to find the shortest possible route that meets the requirements. The city is laid out in a square grid pattern, and is large enough that for the sake of the problem it can be considered infinite.

Input

Input will consist of a single integer N (1 ≤ N ≤ 106), the number of city blocks that must be enclosed by the route.

Output

Print the minimum perimeter that can be achieved.

Examples

Input

4


Output

8


Input

11


Output

14


Input

22


Output

20

Note

Here are some possible shapes for the examples:

<image>
#include <bits/stdc++.h>
using namespace std;
void run_code_sublimetext3() {}
long long n, A[1000100];
int32_t main() {
  run_code_sublimetext3();
  ios_base::sync_with_stdio(false);
  cin >> n;
  long long k = sqrt(n);
  long long ans = k * 4;
  if (n == k * k)
    cout << ans;
  else if (n - k * k <= k)
    cout << ans + 2;
  else
    cout << ans + 4;
}
