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: Accepted)

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < (int)n; i++)
typedef long long ll;


int main(){
  string s;
  cin >>s;
  int n = s.size();
  int ans = 110, ans_temp, left;
  string letter = "abcdefghijklmnopqrstuvwxyz";
  
  rep(j, n){
    left = -1, ans_temp = -1;
    rep(i, n){
      if(s.at(i) == s.at(j)){
        ans_temp= max(abs(i-left-1), ans_temp);
        left = i;
      }
    }
      ans_temp=max(ans_temp, n-1-left);
      ans=min(ans, ans_temp);
    }
    cout << ans;
  }