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)
freq = []
for i in range(26):
    freq.append(0)
d = []
for i in range(n):
    d.append(0)
for i in range(n):
    d[i] = d[i - 1]
    if freq[ord(s[i]) - ord('a')] == 0:
        d[i] = d[i - 1] + 1
        freq[ord(s[i]) - ord('a')] += 1
freq = []
for i in range(26):
    freq.append(-1)
t = d[n - 1] // 2
k = 0
i, j = 0, 0
c = 0
while i >= 0 and j <= n - 1 and i <= j:
    if freq[ord(s[j]) - ord('a')] == -1:
        freq[ord(s[j]) - ord('a')] = 1
    else:
        c -= (freq[ord(s[j]) - ord('a')] == 0)
        freq[ord(s[j]) - ord('a')] += 1
    if d[j] - c > t:
        k = max(k, j - i + 1)
        if freq[ord(s[i]) - ord('a')] != -1:
            freq[ord(s[i]) - ord('a')] -= 1
        c += (freq[ord(s[i]) - ord('a')] == 0)
        i += 1
    j += 1
while d[n - 1] - c <= t:
    i -= 1
    c -= (freq[ord(s[i]) - ord('a')] == 0)
    freq[ord(s[i]) - ord('a')] += 1
    k = max(k, n - i)
print(k)