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
from collections import defaultdict

s = input()

if len(set(s)) == 1:
    print(1)
elif len(set(s)) == len(s):
    print((len(s) // 2) + 1)
else:
    dist = defaultdict(lambda: (0, 0))
    for i, c in enumerate(s):
        if dist[c] == (0, 0):
            dist[c] = (i, float('-inf'))
        else:
            dist[c] = (i, max(i - dist[c][0], dist[c][1]))
            # if dist[c][1] - dist[c][0] < i - dist[c][1]:
            #     dist[c] = (dist[c][1], i)
    
    m = float('inf')
    for k in dist:
        if dist[k][1] > float('-inf'):
            m = min(m, dist[k][1])

    print(m)