Longest Distinct Run

You are given a string s. A distinct run is a contiguous substring in which no character repeats. Report the length of the longest distinct run in s.

Input format

Line 1: an integer n, the length of the string. Line 2: the string s. It contains exactly n characters and no spaces. If n is 0 this line is empty.

Output format

A single integer: the length of the longest contiguous substring of s whose characters are all distinct. Output 0 if s is empty.

Constraints

• 0 ≤ n ≤ 100000
• Each character of s is a printable ASCII character (code 33..126); there are no spaces.