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: Wrong Answer)

import math
s = input()
s_li = list(s)

import collections
c = collections.Counter(s_li)
common_li = c.most_common()
# [('a', 4), ('c', 2), ('b', 1)]
sp_li = s.split(common_li[0][0])

#print(sp_li)
def check(sp_li):
    count = []
    if len(sp_li)==0:
        return 0
    else:
        count = []
        for i,s in enumerate(sp_li):
            count.append(len(s))
        return max(count)


all_li = []
kaisuu = 0
for i,c in enumerate(common_li):
    #print(common_li,c[0],c[1])
    if i == 0:
        kaisuu = c[1]
    else:
        #print(type(c[1]),type(kaisuu),'aaaaaaaa')
        if c[1]!=kaisuu:
            break
    sp_li = s.split(c[0])
    all_li.append(check(sp_li))

#print(all_li)
print(min(all_li))