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 (3.8.2) (judge verdict: Accepted)

import sys
input = sys.stdin.readline
from collections import defaultdict
from itertools import accumulate


def read():
    s = input().strip()
    return s,


def solve(s):
    z = defaultdict(list)
    for i in range(len(s)):
        z[s[i]].append(i)
    ans = 99999
    for k, v in z.items():
        prev = -1
        diffmax = 0
        for i in v:
            diffmax = max(diffmax, i-prev-1)
            prev = i
        diffmax = max(diffmax, len(s)-v[-1]-1)
        ans = min(ans, diffmax)
    return ans


if __name__ == '__main__':
    inputs = read()
    print("%s" % solve(*inputs))