Least Distance
Mr. John has a habit of implementing new programming methods. This time he needs your help to solve a problem. He needs a method such that it accepts a series of numbers (all in single digits) and returns a typical answer. The answer must be the least distance between any two ADJACENT numbers.

For Example: If the series of numbers submitted is :4 8 6 1 2 9 4 The output must yield '1' since the least difference between 2 neighbouring numbers is 1 i.e between 1 and 2.
Note that order of numbers do not matter. In above example, 2 may have appeared before 1.
Neglect if the difference is a negative number.

Input
First line of input must contain a series of numbers.
All numbers must be between 0 and 9 i.e. single digits.

Output
Second Line is the output of the given input.

Example

Input:
4 8 6 1 2 9 4

Output:
1

Input:
5 7 4 9 7 2

Output:
2

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