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 sys import stdin,stdout
input = stdin.readline
from math import inf
s = list(map(str,input().split()))
s = s[0]
left = 0
right = len(s)
mid = left + (right-left)//2
min1 = inf
while left <= right:
    mid = left + (right-left)//2
    dct1 = {}
    for i in range(mid):
        if s[i] in dct1.keys():
            dct1[s[i]] += 1
        else:
            dct1[s[i]] = 1
    for j in range(mid,len(s)):
        if s[j] in dct1.keys():
            if dct1[s[j]] > 0:
                dct1[s[j]] += 1
        if s[j-mid] in dct1.keys():
            dct1[s[j-mid]] -= 1
    check = 0
    for g in dct1.keys():
        if dct1[g] > 0:
            min1 = min(min1,mid)
            check = 1
            break
    if check == 1:
        right = mid - 1
    else:
        left = mid + 1
print(min1)