A. Hexagonal Numberstime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputHexagonal numbers are figurate numbers which can be calculated using the formula hn = 2n2 - n. You are given n; calculate n-th hexagonal number.InputThe only line of input contains an integer n (1 ≤ n ≤ 100).OutputOutput the n-th hexagonal number.ExamplesInput3Output15Input6Output66
Input3
Output15
['*special problem', '*1100']