【CF MEMSQL 3.0 B. Lazy Security Guard】

time limit per test 2 seconds

memory limit per test 256 megabytes

input standard input

output standard output

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:

 

【翻译】有n个长度为1的正方形块拼在一起，求最小周长。

题解：
     ①先对n开根的出近似边长x。

     ②尝试周长：x*x ,x*(x+1), (x+1)*(x+1),只要块数大于n,输出最小值就可以了。

#include<stdio.h>
#include<math.h>
using namespace std;
int n,a;
int main()
{
	scanf("%d",&n);
	a=floor(sqrt(1.0*n)+0.0001);
	if(a*a>=n)printf("%d\n",4*a);
	else if(a*(a+1)>=n)printf("%d\n",4*a+2);
	else if((a+1)*(a+1)>=n)printf("%d\n",4*a+4);return 0;
}//Paul_Guderian