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'

k = len(s)
left = 0
right = len(s)
found = False

ab_ = [0] * 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):
    left = 0
    right = len(s)

    while right - left > 1:
        to_check = (left + right) // 2

        for i in range(len(s) - to_check):
            found = False

            for j in range(i, i + to_check):
                if s[j] == ab[sym]:
                    found = True
                    break

            if not found:
                left = to_check

        if found:
            right = to_check

    if right < k:
        k = right

print(k + 1)
