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 (Clang 3.8.0) (judge verdict: Accepted)

#include <stdio.h>
#include <string.h>

int main(void){
	char s[105];
	scanf("%[^\n]", s);
#ifdef DEBUG
printf("%d\n", strlen(s));
#endif
	int min = 114514;
	for(char a = 'a'; a <= 'z'; a++){
		int count = 0;
		int max = 0;
		for(int i = strlen(s)-1; i >= 0; i--){
			if(s[i] == a){
				if(max < count){
					max = count;
				}
				count = 0;
			}
			else count++;
		}
		if(max < count){
			max = count;
		}
		if(min > max){
			min = max;
		}
	}
	printf("%d\n", min);
	return 0;
}