#include <bits/stdc++.h>
long long INF = (1ll << 61);
using namespace std;
int main(int argc, char* argv[]) {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long k, n;
  cin >> n;
  k = 0;
  while (k * k < n) {
    k++;
  }
  if (k * k - n < k) {
    cout << 4 * k << endl;
  } else {
    cout << 4 * k - 2 << endl;
  }
  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>
long long INF = (1ll << 61);
using namespace std;
int main(int argc, char* argv[]) {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long k, n;
  cin >> n;
  k = 0;
  while (k * k < n) {
    k++;
  }
  if (k * k - n < k) {
    cout << 4 * k << endl;
  } else {
    cout << 4 * k - 2 << endl;
  }
  return 0;
}

```