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
st = input()
l = len(st)
ls = list(set(st))
dt = dict()
for i in range(l):
    for j in range(i+1, l):
        if(st[i]==st[j]):
            if(st[i] in dt):
                dt[st[i]] = max(j-i, dt[st[i]])
            else:
                dt[st[i]] = j-i
            break
for k in ls:
    if k not in dt.keys():
        dt[k]=l
for k in dt.keys():
    for i in range(l):
        if(st[i]==k):
            dt[k] = max(i+1, dt[k])
            break
    
    for i in range(l-1, -1, -1):
        if(st[i]==k):
            dt[k] = max(l-i, dt[k])
            break
        
flag = 0
for k in dt.keys():
    if dt[k] != l:
        flag = 1
if flag==0:
    print(int(l/2) + 1)
    exit()

ans = dt[st[1]]
for v in dt.values():
    if v<ans:
        ans=v
print(ans)