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 9.2.1) (judge verdict: Runtime Error)

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(void){
    int min=100;
    char str[100];
    char original[100];
    scanf("%s",str);
    strcpy(original,str);
    int length=strlen(str);

    int count=0;
    int flag=0;
    for(int i=0;i<length;i++){
        if(str[0]!=str[i]) flag++;
    }
    if(flag==0){
        printf("0\n");
        return 0;
    }
    for(int i=0;i<length;i++){
        count=0;
        strcpy(str,original);
        while(1){
            int flag2=0;
            for(int j=0;j<length-1-count;j++){
                if(str[j]==str[i] || str[j+1]==str[i]) {
                    str[j]=str[i];
                    flag2++;
                }
                //printf("%c",str[j]);
            }
            //printf("\n");
            if(flag2==length-1-count) break;
            count++;
        }
        count++;
        if(min>count) min=count;
        //printf(":%d\n",min);
    }

    printf("%d\n",min);

    return 0;
}