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>
__author__ = 'Alexander'

def Task(inp1):
    n = int(inp1)
    sqr = [1]
    least = 1
    for i in range(2, 1001):
        least = i
        sqr.append(i**2)
        if n >= sqr[i-2] and n < sqr[i-1]:
            break
    least -= 1
    resid = n - sqr[-2]
    if resid == 0:
        res = least*4
    elif resid <= least:
        res = least*4 + 2
    else:
        res = least*4 + 4
    return res

def Main():
    inp1 = input()
    outp = Task(inp1)
    print("{}\n".format(outp))

def Test():
    #These "asserts" using only for self-checking and not necessary for auto-testing
    assert Task(4) == 8

Main()
# Test()