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 Python (3.4.3) (judge verdict: Accepted)

import sys
from collections import Counter, defaultdict
import numpy as np


def input():
    return sys.stdin.readline().strip()


sys.setrecursionlimit(10 ** 9)


def main():
    S = list(input())
    C = Counter(S)
    K = C.keys()
    answer = []
    for k in K:
        cnt = 0
        counter = []
        for s in S:
            if s == k:
                counter.append(cnt)
                cnt = 0
            else:
                cnt += 1
        counter.append(cnt)
        answer.append(max(counter))
    print(min(answer))


if __name__ == "__main__":
    main()