A security log is a string s of lowercase letters; each letter identifies the operator who was on duty at that moment. The log must be split into contiguous, non-empty substrings called shifts (covering the whole string in order, left to right) such that every letter of the alphabet that appears in s appears within a single shift only (it must never appear in two different shifts). Among all valid splits, print the number of shifts in the split that uses the maximum possible number of shifts.
Input format
Line 1: the string s, consisting only of lowercase English letters.
Output format
A single integer: the maximum number of shifts in a valid split of s.
Constraints
- 1 <= length of s <= 14