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Problem Statement

Snuke can change a string $t$ of length $N$ into a string $t'$ of length $N - 1$ under the following rule:

• For each $i$ ($1 ≤ i ≤ N - 1$), the $i$-th character of $t'$ must be either the $i$-th or $(i + 1)$-th character of $t$.

There is a string $s$ consisting of lowercase English letters. Snuke's objective is to apply the above operation to $s$ repeatedly so that all the characters in $s$ are the same. Find the minimum necessary number of operations.

Constraints

• $1 ≤ |s| ≤ 100$
• $s$ consists of lowercase English letters.

Sample Input 1

serval

Sample Output 1

3

One solution is: serval → srvvl → svvv → vvv.

Sample Input 2

jackal

Sample Output 2

2

One solution is: jackal → aacaa → aaaa.

Sample Input 3

zzz

Sample Output 3

0

All the characters in $s$ are the same from the beginning.

Sample Input 4

whbrjpjyhsrywlqjxdbrbaomnw

Sample Output 4

8

In $8$ operations, he can change $s$ to rrrrrrrrrrrrrrrrrr.