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.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int min = Integer.MAX_VALUE;
		for (char c = 'a'; c <= 'z'; c = (char)(c + 1)) {
			int max = 0;
			int current = 0;
			String t = String.valueOf(c);
			int idx = s.indexOf(t);
			while (idx != -1) {
				if (max < idx - current) {
					max = idx - current;
				}
				current = idx + 1;
				idx = s.indexOf(t, current);
			}
			if (max < s.length() - current + 1) {
				max = s.length() - current;
			}
			if (min > max) {
				min = max;
			}
		}
		System.out.println(min);
	}
}