#include <bits/stdc++.h>
using namespace std;
int main() {
  long long x, y, ans, i, j, n, m, p, mini, r;
  while (scanf("%lld", &n) == 1) {
    r = sqrt(n);
    if (r * r == n)
      ans = 4 * r;
    else {
      x = n - r * r;
      y = abs(n - ((r + 1) * (r + 1)));
      if (x > y)
        ans = 4 * (r + 1);
      else
        ans = 2 * (r + (r + 1));
    }
    printf("%lld\n", ans);
  }
  return 0;
}

### Prompt

In cpp, your task is to solve the following problem:

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>

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
int main() {
  long long x, y, ans, i, j, n, m, p, mini, r;
  while (scanf("%lld", &n) == 1) {
    r = sqrt(n);
    if (r * r == n)
      ans = 4 * r;
    else {
      x = n - r * r;
      y = abs(n - ((r + 1) * (r + 1)));
      if (x > y)
        ans = 4 * (r + 1);
      else
        ans = 2 * (r + (r + 1));
    }
    printf("%lld\n", ans);
  }
  return 0;
}

```