Summing Natural Numbers

Given a non-negative integer n, compute the sum of all integers from 1 to n inclusive. Use the formula: \( S = \frac{n(n+1)}{2} \) to calculate the sum.

The input consists of a single integer n provided on one line. You are to output the computed sum.

inputFormat

A single integer n (0 ≤ n ≤ 10^9).

outputFormat

Output a single integer which is the sum of all numbers from 1 to n.

sample

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