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>
import math
from collections import defaultdict
ml=lambda:map(int,input().split())
ll=lambda:list(map(int,input().split()))
ii=lambda:int(input())
ip=lambda:input()

"""========main code==============="""

t=1
  
for _ in range(t):
    n=ii()
    x=int(math.sqrt(n))
    ans=x*2
    n-=x*x
    w=n//x
    
    if(n%x==0):
        ans+=2*(x+w)
    else:
        ans+=2*(x+1+w)
    print(ans)    
        	 					 						 	 	 	 		