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.io.InputStream;
import java.io.PrintStream;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	InputStream in = System.in;
	PrintStream out = System.out;


	boolean check(String s, char c) {
		for(int i=0;i<s.length();i++) {
			if(s.charAt(i) != c) {
				return false;
			}
		}
		return true;
	}

	int f(String s, char c) {
		if(check(s,c)) {
			return 0;
		}

		StringBuffer sb = new StringBuffer();

		for(int i=0;i<s.length()-1;i++) {
			if(s.charAt(i) == c || s.charAt(i+1) == c) {
				sb.append(c);
			}else {
				sb.append(s.charAt(i));
			}
		}

		return f(sb.toString(), c) + 1;

	}

	public void _main(String[] args) {
		Scanner sc = new Scanner(in);

		String s = sc.next();

		sc.close();

		int ans = Integer.MAX_VALUE;

		for(char c='a';c<='z';c++) {
			ans = Math.min(ans, f(s,c));
		}

		out.println(ans);

	}

	public static void main(String[] args) {
		new Main()._main(args);
	}
}