#include <bits/stdc++.h>
using namespace std;
int squareroot(int x) {
  for (int k = 0; k < x; k++) {
    if (k * k <= x && (k + 1) * (k + 1) > x) {
      return k;
      break;
    }
  }
}
int main() {
  int x;
  cin >> x;
  int y = squareroot(x);
  if (y * y == x)
    cout << 4 * y << endl;
  else if (y * (y + 1) < x)
    cout << (y + 1) * 4;
  else
    cout << 2 * y + 2 * (y + 1);
}

### 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 squareroot(int x) {
  for (int k = 0; k < x; k++) {
    if (k * k <= x && (k + 1) * (k + 1) > x) {
      return k;
      break;
    }
  }
}
int main() {
  int x;
  cin >> x;
  int y = squareroot(x);
  if (y * y == x)
    cout << 4 * y << endl;
  else if (y * (y + 1) < x)
    cout << (y + 1) * 4;
  else
    cout << 2 * y + 2 * (y + 1);
}

```