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Problems

Difference of middle

Difference of middle

Time limit 1 second
Memory limit 128 MiB

Four integers a, b, c, d are given. Find the difference between the second and the third biggest element.

Input data

Four integers a, b, c, d. All numbers do not exceed 30000 by absolute value.

Output data

Print one number - the difference between the second and the third biggest element.

Examples

Input example #1
4 5 7 1
Output example #1
1