题目描述

You have a keyboard with $25$ keys. Initially, key $i$ ($1 \leq i \leq 25$) is mapped to the $i$-th lowercase English letter, i.e., key $1$ to ‘a’, key $2$ to ‘b’, ..., and key $25$ to ‘y’. You also have an empty string $T$.

You can perform the following two operations any number of times, in any order:

1. Choose an integer $i$ ($1 \leq i \leq 25$) and a lowercase English letter $c$, and change the mapping of key $i$ to $c$. This operation costs $1$.
2. Choose an integer $i$ ($1 \leq i \leq 25$), and append the letter currently mapped to key $i$ to the end of $T$. This operation costs $0$.

You are given a string $S$ consisting of lowercase English letters. Find the minimum total cost required to make $T$ equal to $S$.

输入格式

The input consists of a single test case in the following format.

The only line contains a string $S$ consisting of lowercase English letters. The length of $S$ is between $1$ and $500\,000$, inclusive.

输出格式

Print the minimum total cost as an integer.

meatthezoo

1

zxcvbnmqwertyuiopasdfghjklzxcvbnm

2