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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int b[26] ={0};

int main(void)
{
    char s[101];
    scanf("%s", s);
    int l = strlen(s);
    for (int i = 0; i < l; ++i){
       b[s[i] -'a'] ++;
    }

    for (int j = 0; j < 26; ++j){
        if (b[j]){
            int k = 0;
            int max = 0;
            for (int i = 0; i < l; ++i){
                if (s[i] == j + 'a'){
                    if (k > max){
                        max = k;
                        k = 0;
                    }
                }
                else
                    k++;
            }
            if (k > max)
                b[j] = k;
            else
                b[j] = max;
        }
        else
            b[j] = 200;
    }
    
    int min = 200;
    for (int j = 0; j < 26; ++j){
        if (b[j] < min){
            min = b[j];
        }
    }
    printf("%d\n", min);
    return 0;
}