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()
def isgood(k):
    d={}
    q=set(s[:k])
    for x in range(26):
        d[chr(x+ord('a'))]=0
    for x in range(k):
        d[s[x]]+=1
    for x in range(k,len(s)):
        d[s[x-k]]-=1
        d[s[k]]+=1
        tmp=q.copy()
        for y in q:
            if d[y]==0:
                tmp.remove(y)
        q=tmp
        if len(q)==0:
            break
    return len(q)>0
l=1
r=len(s)+1
while r-l>1:
    mid=(r+l)//2
    if isgood(mid):
        r=mid
    else:
        l=mid
print(r if not isgood(1) else 1)