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>
n=int(input())
l=1
r=n
m=0
while(r-l>1):
    m=int((l+r)/2)
    if m*m>n:
        r=m
    else:
        l=m
if m*m>n:
    m-=1
if n>2 and m*m!=n:
    if m*m+m>=n:
        print(4*m+2)
    else:
        print(4*m+4)
else:
    if n==1:
        print(4)
    elif n==2:
        print(6)
if m*m==n:
    print(4*m)