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
from collections import defaultdict 
input = sys.stdin.readline

def main():
    word = [ *input().strip() ]
    n = len(word)

    letters_map = defaultdict(list)
    for i in range(27):
        letters_map[i] = [-1, -1]

    for index, letter in enumerate(word):
        letter_key = ord(letter) - 97
        prev_index, max_diff = letters_map[letter_key]
        new_diff = abs(index - prev_index)
        letters_map[letter_key][1] = max(max_diff, new_diff)
        letters_map[letter_key][0] = index

    # Compare with lenghts
    for key in letters_map.keys():
        prev_index, max_diff = letters_map[key]
        new_diff = abs(n - prev_index)
        letters_map[key][1] = max(max_diff, new_diff)

    answer = float("inf")
    for index, diff in letters_map.values():
        if index != -1:
            answer = min(answer, diff)

    print(answer)

if __name__ == "__main__":
    main()
