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, exit, setrecursionlimit
from collections import deque
input = stdin.readline
lmi = lambda: list(map(int, input().split()))
mi = lambda: map(int, input().split())
si = lambda: input().strip('\n')
ssi = lambda: input().strip('\n').split()
mod = 10**9+7

def check(k):
    ok = [False for i in range(26)]
    cnt = [0 for i in range(26)]
    for i in range(k):
        ok[ord(s[i])-ord("a")] = True
        cnt[ord(s[i]) - ord("a")] += 1
    for i in range(k, len(s)):
        cnt[ord(s[i]) - ord("a")] += 1
        cnt[ord(s[i-k]) - ord("a")] -= 1
        if cnt[ord(s[i-k]) - ord("a")] == 0:
            ok[ord(s[i - k]) - ord("a")] = False
    for i in ok:
        if i:
            return True
    return False
s = si()
l = 0
r = len(s)
while l < r:
    mid = l + r >> 1
    if check(mid):
        r = mid
    else:
        l = mid+1
print(l)