Problem:
Score : 300 points

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.

Input

Input is given from Standard Input in the following format:

s

Output

Print the minimum necessary number of operations to achieve the objective.

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.

Solution in PHP (5.6.30) (judge verdict: Wrong Answer)

<?php
$str = trim(fgets(STDIN));
$list = str_split($str);
$cnts = array_count_values($list);
$patt = count($cnts);
if ($patt == 1) {
    echo '0';
} else {
    $max = max($cnts);
    if ($max == min($cnts)) {
        echo floor($patt / 2); 
    } else {
        $keys = array_keys($cnts, $max);
        if (count($keys) > 1) {
            $num = 0;
            foreach ($keys as $key) {
                $num += $cnts[$key];
            }
            $num -= count($keys);
            echo $num;
        } else {
            echo $cnts[$keys[0]];
        }
    }
}
echo "\n";