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 collections
s = list(input())
#print(s)
c = collections.Counter(s)
l = list(c.items())
l = sorted(l, key = lambda x : x[1], reverse=True)
#print(l)

h = []
tmp = l[0][1]

for i in range(len(l)):
     if l[i][1] >= tmp:
          h.append(l[i][0])
     else:
        break

#print(h)

ans = []

for i in range(len(h)):
    tmp = [_ for _, x in enumerate(s) if x == h[i]]
#    print(h[i])
#    print(tmp)
    lll = []
    for j in range(len(tmp)):
        if j == 0:
            lll.append(tmp[j])
        else:
            lll.append(tmp[j] - tmp[j-1] - 1)
    lll.append(len(s) - tmp[len(tmp) - 1] - 1)
    ans.append(max(lll))
#    print(lll)


#print(ans)
print(min(ans))