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=str(input())
d={}
for i in range(len(s)):
	if(s[i] not in d):
		d[s[i]]=[i]
	else:
		if(len(d[s[i]])>=2):
			if(i-d[s[i]][len(d[s[i]])-1]==d[s[i]][len(d[s[i]])-1]-d[s[i]][len(d[s[i]])-2]):
				d[s[i]].append(i)
			else:
				d[s[i]]=-1
		else:
			d[s[i]].append(i)
m=10000001
for i in d:
	if(len(d[i])>=2 and d[i][1]-d[i][0]<m):
		m=d[i][1]-d[i][0]
if(m==10000001):
	if(len(s)%2==1):
		print(int(len(s)/2)+len(s)%2)
	else:
		print(1)
else:
	print(m)
	
