#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n;
  while (scanf("%lld", &n) == 1) {
    long long m = sqrt(n);
    long long ans = 0;
    if (m * m >= n)
      ans = 2 * (m + m);
    else if (m * (m + 1) >= n)
      ans = 2 * (m + m + 1);
    else if ((m + 1) * (m + 1) >= n)
      ans = 2 * (m + 1 + m + 1);
    else if ((m + 1) * (m + 2) >= n)
      ans = 2 * (m + 2 + m + 1);
    else if ((m + 2) * (m + 2) >= n)
      ans = 2 * (m + 2 + m + 2);
    else
      assert(0);
    printf("%lld\n", ans);
  }
  return 0;
}

### Prompt

Please create a solution in CPP 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;
int main() {
  long long n;
  while (scanf("%lld", &n) == 1) {
    long long m = sqrt(n);
    long long ans = 0;
    if (m * m >= n)
      ans = 2 * (m + m);
    else if (m * (m + 1) >= n)
      ans = 2 * (m + m + 1);
    else if ((m + 1) * (m + 1) >= n)
      ans = 2 * (m + 1 + m + 1);
    else if ((m + 1) * (m + 2) >= n)
      ans = 2 * (m + 2 + m + 1);
    else if ((m + 2) * (m + 2) >= n)
      ans = 2 * (m + 2 + m + 2);
    else
      assert(0);
    printf("%lld\n", ans);
  }
  return 0;
}

```