#include <bits/stdc++.h>
using namespace std;
long long n, i, m, k, l, r, d, ans;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> n;
  l = 1;
  r = n;
  while (l <= r) {
    d = (l + r) / 2;
    if (d * d >= n) {
      m = d;
      r = d - 1;
    } else
      l = d + 1;
  }
  k = (n + m - 1) / m;
  n = m * k;
  ans = m * 4 - ((m * m - n) / m * 2);
  cout << ans << '\n';
  return 0;
}

### Prompt

Please formulate a CPP solution to 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;
long long n, i, m, k, l, r, d, ans;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> n;
  l = 1;
  r = n;
  while (l <= r) {
    d = (l + r) / 2;
    if (d * d >= n) {
      m = d;
      r = d - 1;
    } else
      l = d + 1;
  }
  k = (n + m - 1) / m;
  n = m * k;
  ans = m * 4 - ((m * m - n) / m * 2);
  cout << ans << '\n';
  return 0;
}

```