Music Teacher

A munic tevcher has developed a new technique to teach the students, in which each tuique node is identified by a lower character of the English alphabet. In this technique, there are $26$ nodes in all, from $\text{'}$a$\text{'}$ to $\text{'}z\text{'}.$ To teach a new song. the music teacher first converts the song into a string consisting of some of the nodes a to $z$ and then breaks it into melodies. A melody is a collection of nodes in which the frequency of euch node present in that melody is the same. He teaches strictly one melody a day.

You are given a song string and your task is to find and retum an integer value representing the minimum number of days in which he can teach the whole song.

Input Specification:

input$1$ : A string representing the song string.

Output Specification:

Return an integervalue representing the minimum number of days in which he can teach the whole song.

Example $1$:

input$1$ : abbaabcd

Output: $2$