You are given a string *s* consisting of lowercase Latin letters. Character *c* is called *k*-dominant iff each substring of *s* with length at least *k* contains this character *c*.

You have to find minimum *k* such that there exists at least one *k*-dominant character.
The first line contains string *s* consisting of lowercase Latin letters (1 ≤ |*s*| ≤ 100000).
none
abacaba
2
zzzzz
1
abcde
3
bcaccacaaabaacaabaaabcbbcbcaacacbcbaaaacccacbbcbaabcbacaacbabacacacaccbbccbcbacbbbbccccabcabaaab
8
daabcdabbabbacacbaacabacbcaabaacac
4
abghim
4
gfliflgfhhdkceacdljgkegmdlhcgkcmlelmbbbmdddgdeeljjhgbbffmemmmkhebgkhadkdajabcjkcgbkgbaeacdedlkklfech
17
a
1
aaabbb
4
ab
2
abbb
2
ob
2
abccba
3
saaaaaaaas
2
axxx
2
abcba
2
abb
2
abcdea
4
axcbb
3
tmivvdcbbfrfogjviirrximhttoskopwrcmkcborcxvr
13
dlchmmuateksgldkckljrovmeuniobjrelqjpnjljlvhpqrjsfklliqpufplgaelevmlcnodbllquubobecem
15
zx
2
zxz
2
bbhdgaefbhf
6
xx
1
zxx
2
cbcada
4
z
1
aab
2
jficc
3
cceeaabfba
5
jk
2
lzeznbwu
5
rr
1
from collections import defaultdict
class Solution:
    def dominantCharacter(self, string):
        # TODO write an algorithm here
        n = len(string)
        dic = {}
        for i in range(len(string)):
            if string[i] not in dic:
                dic[string[i]] = [i]
                if i != 0 and string[i] != string[0]: dic[string[i]].append(-1)
                if i != len(string)-1 and string[-1] != string[i]: dic[string[i]].append(n)
            else: dic[string[i]].append(i)
        
        answer = 100001
        for key in dic:
            lst, temp_answer = dic[key], 0
            lst.sort()
            for i in range(1, len(lst)):
                temp_answer = max(temp_answer, lst[i] - lst[i-1])
            answer = min(answer, temp_answer)
            
        return answer if answer > 0 else 1
            
if __name__ == "__main__":
    solution = Solution()
    string = input()
    
    print(solution.dominantCharacter(string))