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 = input()
if len(s) == 1:
    print(1)
    exit()

def f(size):
    for l in 'abcdefghijklmnopqrstuvwxyz':
        found = {}
        for i in range(size):
            if s[i] not in found:
                found[s[i]] = 1
            else:
                found[s[i]] += 1
        i = 0
        if l not in found:
            continue
        f=1
        i=0
        for j in range(size, len(s)):
            found[s[i]] -=1
            if found[s[i]] == 0:
                del found[s[i]]
            i+=1
            if s[j] not in found:
                found[s[j]] = 1
            else:
                found[s[j]] += 1

            if l not in found:
                f=0
                break
        if f:
            return True

    return False


l=1
r=len(s)-1

ans = r
while l<=r:
    mid = l + (r-l)//2
    if f(mid):
        ans = mid
        r = mid-1
    else:
        l = mid+1

print(ans)