Number of even numbers#9902

Number of even numbers

1 second
64 megabytes
Very easy

The program receives a natural number as input. Your task is to output the count of even natural numbers that are less than or equal to .

Input

A natural number , where does not exceed 10^{18}.

Output

The answer to the problem — the count of even natural numbers that do not exceed .

Examples

Example 2

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Example 1

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