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()
n = len(s)
last_index, m = [], []
for i in range(26):
    last_index.append(-1)
    m.append(-1)
for i in range(n):
    j = ord(s[i]) - ord('a')
    if last_index[j] == -1:
        m[j] = max(m[j], i + 1)
    else:
        m[j] = max(m[j], i - last_index[j])
    last_index[j] = i
last_index = []
for i in range(26):
    last_index.append(-1)
for i in range(n - 1, -1, -1):
    j = ord(s[i]) - ord('a')
    if last_index[j] == -1:
        m[j] = max(m[j], n - i)
    else:
        m[j] = max(m[j], i - last_index[j])
    last_index[j] = i
k = 1e5 + 1
for x in s:
    j = ord(x) - ord('a')
    k = min(k, m[j])
print(k)