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 (7.3.0) (judge verdict: Accepted)

from math import ceil

s=input()
x='abcdefghijklmnopqrstuvwxyz'
ans=1000


def greedy(i,s,cnt):
    if s.count(s[0])==len(s):
        return cnt
    t=''
    for j in range(len(s)-1):
        if s[j]==i or s[j+1]==i:
            t+=i
        
        else:
            t+=s[j]
    
    return greedy(i,t,cnt+1)


for i in x:
    ans=min(ans,greedy(i,s,0))


print(ans)