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;
int main() {
  int n, x, I = 0;
  cin >> n;
  for (int i = 1; i <= 1000; i++) {
    if ((i * i) >= n) {
      x = (i * i);
      I = i;
      break;
    }
  }
  int res = x - n;
  int ans1 = -1, y = 0, z = 0;
  if (res == 0) {
    ans1 = I * 4;
  }
  if ((res / I) >= 1) {
    y = (I * (I - (res / I)));
    z = res % I;
    ans1 = (I * 2) + ((I - (res / I)) * 2);
  }
  if ((res / I) == 0) {
    ans1 = I * 4;
  }
  cout << ans1 << endl;
  return 0;
}
