#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL);
  long long n, ans, a, b, c, d;
  cin >> n;
  a = ceil(sqrt(n));
  b = a;
  c = b - 1;
  d = b + 1;
  if (a * c >= n)
    ans = a + c;
  else if (a * b >= n)
    ans = a + b;
  else
    ans = a + d;
  cout << ans * 2;
  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() {
  ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL);
  long long n, ans, a, b, c, d;
  cin >> n;
  a = ceil(sqrt(n));
  b = a;
  c = b - 1;
  d = b + 1;
  if (a * c >= n)
    ans = a + c;
  else if (a * b >= n)
    ans = a + b;
  else
    ans = a + d;
  cout << ans * 2;
  return 0;
}

```