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
def binary_search(up,lo):
    while lo<=up:
        mid=(up+lo)//2
        if find_k(mid):
            ans=mid
            up=mid-1
        else:
            lo=mid+1
    return ans

s=str(input())
n=len(s)
k_max=n//2+1
        
def find_k(k):
    ans=True
    P=set(s[0:k])
    in_sstr=[[p,True] for p in P]
    k_a=len(in_sstr)
    for i in range(1,n-k):
        Q=set(s[i:i+k])
        for j in range(k_a):
            if in_sstr[j][0] not in Q:
                in_sstr[j][1]=False
    return ans

print(binary_search(k_max,1))
 							      			 	 							  		