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# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Linq;//リストの使用
using System.Collections.Generic;
using System.Text;//テキストの高速出力に必要
class Program
{
	static void Main()
	{
		string s = Console.ReadLine();
    string alphabets = "abcdefghijklmnopqrstuvwxyz";//26文字
    int n = s.Length;
		long answer = 1000;
    long answerMemo = 0;
    long answerMemoMax = 0;
    
    for(int i = 0; i < 26; i++)
    {
      for(int j = 0; j < n; j++)
      {
        if(s[j] == alphabets[i])
        {
          answerMemoMax = Math.Max(answerMemoMax, answerMemo);
          answerMemo = 0;
        }else
        {
          answerMemo++;
        }
        answerMemoMax = Math.Max(answerMemoMax, answerMemo);
      }
      //Console.WriteLine(i + " " +answerMemoMax);
      answer = Math.Min(answer, answerMemoMax);
      answerMemo = 0;
      answerMemoMax = 0;
    }

    
		Console.WriteLine(answer);
	}
}