#include <bits/stdc++.h>
#pragma GCC target("sse4,avx")
void run(std::istream &in, std::ostream &out) {
  int n;
  in >> n;
  int min = n + 1;
  for (int i = 2; i * i <= n; i++) {
    int v = i + (n + i - 1) / i;
    min = std::min(min, v);
  }
  out << 2 * min << "\n";
}
int main() {
  std::cin.sync_with_stdio(false);
  std::cin.tie(nullptr);
  run(std::cin, std::cout);
  return 0;
}

### Prompt

Your challenge is to write 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>
#pragma GCC target("sse4,avx")
void run(std::istream &in, std::ostream &out) {
  int n;
  in >> n;
  int min = n + 1;
  for (int i = 2; i * i <= n; i++) {
    int v = i + (n + i - 1) / i;
    min = std::min(min, v);
  }
  out << 2 * min << "\n";
}
int main() {
  std::cin.sync_with_stdio(false);
  std::cin.tie(nullptr);
  run(std::cin, std::cout);
  return 0;
}

```