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 = str(input())

ab = 'abcdefghijklmnopqrstuvwxyz'
ab_ = [0] * 26
answer = [1000000000] * 26

for i in range(26):
    for j in range(len(s)):
        if s[j] == ab[i]:
            ab_[i] += 1

res = 0
for i in range(26):
    if ab_[i] != 0:
        res += 1

if res == 1:
    print(1)
    exit(0)

for sym in range(26):
    positions = [-1]
    delta = 0

    for i in range(len(s)):
        if s[i] == ab[sym]:
            positions.append(i)

    positions.append(len(s))

    if len(positions) > 1:
        for i in range(len(positions) - 1):
            if (positions[i + 1] - positions[i]) > delta:
                delta = positions[i + 1] - positions[i]
    if delta > 0:
        answer[sym] = delta

print(min(answer))
