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 PyPy3 (2.4.0) (judge verdict: Accepted)

import itertools
import math
from collections import deque
from collections import defaultdict
from itertools import permutations
import heapq
import bisect
from collections import Counter
from itertools import*
from bisect import bisect_left,bisect_right
from collections import Counter
inf = 10**10
from functools import reduce

s = input()
ans = len(s)
for i in set(s):
    t = s.split(i)
    c = 0
    for j in t:
        c = max(c,len(j))
    ans = min(ans,c)
print(ans)