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>
mas = list(map(int, input().split()))
t = mas[0]
kv = 1
while((kv + 1) ** 2 <= t):
    kv += 1
s = 4 * kv
if (t - kv ** 2 == 0):
    print(s)
elif (t - kv ** 2 <= kv):
    print(s + 2)
else:
    print(s + 4)