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
inp=lambda:map(int,input().split())
s=input()

l=len(s)
lab=[0]*27
m=[-1]*27

for i in range(27):
    fl=0
    d=0
    for j in range(l):
        if s[j]==chr(i+ord('a')):
            fl=1
            break

    k=j

    if fl==0: continue

    fl=0
    for j in range(k+1,l):
      if s[j]!=chr(i+ord('a')):
          d+=1
      else:
          fl=1
          m[i]=max(m[i],d+1)
          d=0
          last=j

   

    if fl==0:
        m[i]=max(k+1,l-k)
    else:
        m[i]=max(m[i],k+1,l-last)

r=10000000

for i in range(27):
    if m[i]>=0: 
        r=min(r,m[i]);

print(r)
