As summer arrives in Teyvat, so have the dandelions. Noelle has taken on the task of removing and decomposing them with their roots. To her convenience, the guild has square-shaped decomposing gadgets that can decompose a dandelion encompassed in the square.

Given the dandelion with maximum radius of ~R~, help Noelle determine the minimum perimeter of the square gadget she will need.

Constraints

~1 \le R \le 10^8~

Input Specification

A single line containing an integer ~R~.

Output Specification

A single line containing the minimum perimeter as an integer.

Sample Input 1

8

Sample Output 1

64

Explanation for Sample 1

A circle of radius ~8~ requires a square of minimum perimeter ~64~.

Sample Input 2

4

Sample Output 2

32

Sample Input 3

17279317

Sample Output 3

138234536