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
import math
import collections
l=list(input())
n=len(l)
l1=[0]*n
d={}
for i in range(n):
    if(l[i] not in d):
        if(i==0):
            d[l[i]]=[i]
        else:
            d[l[i]]=[-1,i]
    else:
        d[l[i]].append(i)
for i in d:
    if(d[i][-1]!=n-1):
        d[i].append(n)
m=n
d=collections.OrderedDict(sorted(d.items()))
for i in d:
    d1=0
    for j in range(len(d[i])-1):
        d1=max(d1,d[i][j+1]-d[i][j])
    for j in range(d1-1,m):
        l1[j]=i
    m=min(m,d1-1)
print(m+1)