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>
#define min(X, Y) ((X) < (Y) ? (X) : (Y))

int is_unique(char *);

int main()
{
	char str[105];
	char cpy[105];
	int ans = 300;

	scanf("%s", str);

	for (int i = 'a'; i <= 'z'; i++) {
		int cnt = 0;
		strcpy(cpy, str);

		while (!is_unique(cpy)) {
			cnt++;

			for (int j = 0; j < strlen(cpy) - 1; j++) {
				if (cpy[j + 1] == i) {
					cpy[j] = cpy[j + 1];
				}
			}
			cpy[strlen(cpy) - 1] = '\0';
		}

		ans = min(ans, cnt);
	}

	printf("%d\n", ans);

	return 0;
}

int is_unique(char *str)
{
	int i = 1;
	while (str[i] != '\0' && str[i] == str[i - 1]) {
		i++;
	}

	if (str[i] == '\0') {
		return 1;
	} else {
		return 0;
	}
}