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
import math
from bisect import bisect_right as br
from collections import deque
#from decimal import Decimal 
 
#from statistics import mode
 
from itertools import combinations as cb
 
def int_arr(): return list(map(int, sys.stdin.readline().strip().split()))
 
def str_arr(): return list(map(str, sys.stdin.readline().strip().split()))
 
def input(): return sys.stdin.readline().strip()
 
 


# sys.stdin = open('K Dominant Character/input.txt', 'r')
# sys.stdout =open('K Dominant Character/output.txt', 'w')

st=input()
d={}
for i in range(len(st)):
    if d.get(st[i],0)==0:
        d[st[i]]=[0,i+1]
    else:
        d[st[i]].append(i+1)

for i in d.keys():
    d[i].append(len(st)-1)

ans=float('inf')
for i in d.values():
    mx=0
    for j in range(1,len(i)):
        mx=max(mx,i[j]-i[j-1])
    ans=min(ans,mx)
print(ans)


    