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

from functools import reduce

# sys.stdin = open('a1.in')


def read_int_list():
    return list(map(int, input().split()))


def read_int_list():
    return int(input())


def read_str_list():
    return input().split()


def read_str():
    return input()


s = read_str()
n = len(s)
c = [set() for l in s]
for i in range(n, 0, -1):
    d = n - i
    for j in range(i):
        c[j].add(s[j + d])
    intersection = reduce(lambda x, y: x & y, c[:i])
    if intersection:
        print(d)
        break