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: Accepted)

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

int main(void){
    char s[120],c[27]="abcdefghijklmnopqrstuvwxyz";
    scanf("%s",s);
    int tmp,count,ans=1e9;
    for (int i=0; i<26; i++){
        count=0;
        tmp=0;
        for (int j=0; j<strlen(s); j++){
            if (s[strlen(s)-1-j]==c[i]){
                if(tmp<count){
                    tmp=count;
                }
                count=0;
            } else {
                count++;
            }
        }
        if(tmp<count){
            tmp=count;
        }
        if(tmp<ans){
            ans=tmp;
        }
    }
    printf("%d\n",ans);
	return 0 ;
}