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, copy
# sys.setrecursionlimit(8000)
# sys.setrecursionlimit(1 << 30)
from collections import Counter, defaultdict

def inp():
    return(int(input()))
def inlt():
    return(list(map(int,input().split())))

def helper(k, n, s):
    left, right = 0, k
    mapping = defaultdict(int)
    Set = set()
    for i in range(k):
        mapping[s[i]] += 1
        Set.add(s[i])
    while right < n:
        mapping[s[left]] -= 1
        mapping[s[right]] += 1
        if mapping[s[left]] == 0 and s[left] in Set:
            Set.remove(s[left])
            if not Set:
                return False
        mapping[s[right]] += 1
        left += 1
        right += 1
    return True

def answer(s):
    left, right = 1, len(s)
    n = len(s)
    while left <= right:
        mid = (left + right) // 2
        if helper(mid, n, s):
            right = mid - 1
        else:
            left = mid + 1
    return left

s = input()
print(answer(s))