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)


s = input()

strs = set(s)


if len(set(s)) == 1:
  print(0)
  exit()

ans = 1000
tmp = 0
for moji in strs:
  s1 = s
  s2 = [""] * (len(s)-1)
  tmp = 0
  flag = True
  while flag == True:
    for i in range(len(s2)):
      if s1[i] == moji or s1[i+1] == moji:
        s2[i] = moji
      else:
        s2[i] = s1[i]
      
    tmp += 1
    s1 = s2
    s2 = [""] * (len(s1)-1)

    if len(set(s1)) == 1:
      flag = False
  ans = min(ans, tmp)   
 
print(ans)