Description

Distribute a pile of apples to n children, ensuring that each child receives at least one apple and that no two children receive the same number of apples. What is the minimum number of apples required to satisfy these conditions?

Input Format

A positive integer n not exceeding 1000, representing the number of children.

Output Format

An integer indicating the minimum number of apples required to meet the conditions.

```output1
36

## Source

CodesOnline