The number of odd numbers between the numbers#9910

The number of odd numbers between the numbers

1 second
64 megabytes
Very easy

Determine and output the count of odd integers that exist between the numbers and .

Input

Two integers provided in a single line, separated by a space, each not exceeding 10^{18}.

Output

The number of odd integers between and .

Examples

Example 1

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Example 2

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