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>
from math import sqrt, floor

def isPerfect(N):
    if (sqrt(N) - floor(sqrt(N)) != 0):
        return False
    else:
        return True

def getClosestPerfectSquare(N):
    if (isPerfect(N)):
        print(N, "0")
        return

    aboveN = -1
    belowN = -1
    n1 = 0

    n1 = N + 1
    while (True):
        if (isPerfect(n1)):
            aboveN = n1
            break
        else:
            n1 += 1

    n1 = N - 1
    while (True):
        if (isPerfect(n1)):
            belowN = n1
            break
        else:
            n1 -= 1

    diff1 = aboveN - N
    diff2 = N - belowN

    if (diff1 > diff2):
        return (belowN,diff2)
    else:
        return (aboveN,-diff1)



N = int(input())

if(isPerfect(N)):
    print(int(sqrt(N)*4))
else:
    ans1 = getClosestPerfectSquare(N)
    a,b = ans1
    #print(a,b)
    if(b>0):
        print(int((sqrt(a)*4)+2))
    elif(b<0):
        print(int(sqrt(a)*4))

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