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()
d = {}
for i in s:
    if i in d:
        d[i] += 1
    else:
        d[i] = 1
maxval = max(d, key=d.get)
max_occur = d[maxval]
if max_occur==1:
    if len(s)%2==0:
        print(len(s)//2 + 1)
    else:
        print((len(s)+1)//2)
else:
    k_dom = []
    for i in d.keys():
        if d[i] > 1:
            k_dom.append(i)
    best = len(s)+1
    for i in k_dom:
        ans = 0
        prev = -1
        for j in range(len(s)):
            if s[j] == i:
                check = j-prev
                prev = j
                if check > ans:
                    ans = check
        if len(s)-prev > ans:
            ans = len(s)-prev
        if ans < best:
            best = ans
    if len(s)%2==0:
        if best > (len(s)//2+1):
            best = (len(s)//2+1)
    else:
        if best > (len(s)+1)//2:
            best = (len(s)+1)//2
    print(best)