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 sys

s = input()

for step in range(1,len(s)+1):
    for i in range(step+1):
        res = [s[x] for x in range(i,len(s),step)]
        if len(set(res)) == 1:
            print(step)
            sys.exit(0)
"""
s = input()

letters = set(s)

dist = dict(zip(letters, [0]*len(letters)))
last = dict(zip(letters, [-1]*len(letters)))

for i in range(len(s)):
    new_dist = i-last[s[i]]
    if dist[s[i]] <= new_dist:
        dist[s[i]] = new_dist
    last[s[i]] = i

if len(letters) == len(s):

    last = dict(zip(letters, [len(letters)]*len(letters)))

    for i in range(len(s)):
        new_dist = last[s[i]]-i
        if dist[s[i]] <= new_dist:
            dist[s[i]] = new_dist
        last[s[i]] = i

print(min(dist.values()))
