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>
b=int(input())
d=1
k=2
n=abs(b-(d**2))
r=abs(b-(k**2))
while True:
	if r>n:
		break
	else:
		d+=1
		k+=1
		n=abs(b-(d**2))
		r=abs(b-(k**2))
h=d**2
g=0
if b>h:
	g=d+d+(d+1)+(d+1)
else:
	g=d+d+d+d
print(g)
