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 collections import defaultdict

def KDominantChExists(k, s, s_size):
    ch2cnt_in_seg = defaultdict(int)
    ch2popularity = defaultdict(int)

    for i in range(s_size):
        ch2cnt_in_seg[s[i]] += 1

        if i < (k - 1):
            continue
        
        l_ind = i + 1 - k
        if l_ind > 0:
            ch2cnt_in_seg[s[l_ind - 1]] -= 1
        
        for ch, cnt in ch2cnt_in_seg.items():
            if cnt > 0:
                ch2popularity[ch] += 1
        
    populs = ch2popularity.values()
    return max(populs) >= (s_size - k + 1)

def Sol(s):
    s_size = len(s)

    l, r = 1, s_size
    
    min_k = s_size
    while l <= r:
        mid = (l + r) // 2
        k_dom_exists = KDominantChExists(k=mid, s=s, s_size=s_size)
        if k_dom_exists:
            min_k = mid
            r = mid - 1
        else:
            l = mid + 1
    
    return min_k



s = input().strip()
min_k = Sol(s)
print(min_k)



