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 <math.h>
#include <time.h>
#include <string.h>
char s[100];
char orgS[100];

int shim(char x){
  int ans = 101;
  int L = strlen(s);
  int check;
  for (int i=0;i<100;i++){
    check = 0;
    for (int j=0;j<L-1;j++){
      if (s[j+1] == x)s[j] = s[j+1];
      if (s[j+1] != x&&s[j] !=x){
        check++;
      }
    }
    if (check == 0){
      ans = i;
      break;
    }
    L--;
  }
  for (int i=0;i<100;i++){
    s[i]=orgS[i];
  }
  return ans;
}


int main(){
  scanf("%s",s);
  for (int i=0;i<100;i++){
    orgS[i] = s[i];
  }
  int best = 101;
  for (char x = 'a';x <= 'z';x++){
    if (best > shim(x))best = shim(x);
  }
  printf("%d\n",best+1);
}