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
s = input()
d = {}
for i in range(len(s)):
    if s[i] not in d.keys():
        d[s[i]] = [i]
    else:
        d[s[i]].append(i)
res = {}
for key in d.keys():
    max_dif = max(d[key][0] + 1, len(s) - d[key][-1])
    for i in range(1, len(d[key])):
        max_dif = max(max_dif, d[key][i] - d[key][i - 1])
    res[key] = max_dif
print(min(res.values()))
