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B. Lazy Security Guard
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

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: