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()

import string

dct = {ch: -1 for ch in string.ascii_lowercase}
distances = {ch: [] for ch in string.ascii_lowercase}
for i, ch in enumerate(s):
   distances[ch].append(i - dct[ch])
   dct[ch] = i

dct = {ch: -1 for ch in string.ascii_lowercase}
distances_backward = {ch: [] for ch in string.ascii_lowercase}

for i, ch in enumerate(s[::-1]):
   distances_backward[ch].append(i - dct[ch])
   dct[ch] = i

ans = 10**9
for ch in set(s):
    m1 = max(distances[ch])
    m2 = max(distances_backward[ch])
    m = max(m1, m2)
    if m < ans:
        ans = m
print(ans)
