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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
import java.util.List;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
//
        String S = new String();
        S = sc.next();

        int min = 200;
        for(int i = 0; i< S.length(); i++){
            int temp = changeNum(S, i);
            if(min > temp){
                min = temp;
            }
        }
        System.out.println(min);
    }

    //strをpos番目の文字にすべて変更する場合の回数
    private static int changeNum(String str, int pos){
        List<Integer> index = new ArrayList<>();
        for(int i =0 ;i<str.length();i++){
            if(str.charAt(i) == str.charAt(pos)){
                index.add(i);
            }
        }

        int ans = str.length() - index.get(index.size()-1);
        int temp = index.get(0) + 1;
        if (ans < temp){
            ans = temp;
        }
        for(int i=(index.size()-1); i > 0; i--){
            if(ans < (index.get(i) - index.get(i-1))){
                ans = index.get(i) - index.get(i-1);
            }
        }
        return (ans - 1);
    }
}