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>
# import sys
# sys.stdin=open("input.in",'r')
# sys.stdout=open("out1.out",'w')
import math as m
n=int(input())
x=int(m.sqrt(n))
p=x*x
peri=4*x
q=n-p
while q>x:
	peri+=2
	q-=x
if q!=0:	
	peri+=2
print(peri)	

