Sum of Even Numbers

Given an integer \( n \), compute the sum of all even numbers between 1 and \( n \) (inclusive). Your task is to implement a solution that reads an integer from standard input and outputs the computed sum.

The sum of even numbers from 1 to \( n \) can be expressed as:

\[ S = \sum_{i=1}^{\lfloor n/2 \rfloor} 2i \]

Make sure your solution handles edge cases correctly.

inputFormat

The input consists of a single integer \( n \) on a single line.

outputFormat

The output should be a single integer representing the sum of all even numbers from 1 to \( n \) (inclusive).

## sample

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