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
from  bisect import bisect_right as br ,bisect_left as bl
from  collections import  defaultdict
def check(mid):
    global s,d

    for word in d:
        flag = True
        for i in range(len(s)-mid+1):
            gr=bl(d[word],i)
            gl=br(d[word],i+mid-1)-1
            if gl-gr>=0 and gr!=len(d[word]) and gl>=0:
                pass
            else:
                flag=False
                break
        if flag:
            return True
    return flag


s=input()
d=defaultdict(list)
for id,i in enumerate(s):
    d[i].append(id)
lo=1
hi=len(s)
ans=None
while lo<=hi:
    mid=(lo+hi)//2
    if check(mid):
        hi=mid-1
        ans=mid
    else:
        lo=mid+1
print(ans)
