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 math
import heapq
from collections import defaultdict, deque
from decimal import *
def r():
    return int(input())
def rm():
    return map(int,input().split())
def rl():
    return list(map(int,input().split()))

'''C K-dominant Character'''
s=input()
a=[[] for i in range(26)]
n=len(s)
for i in range(n):
    a[ord(s[i])-97].append(i)

res=math.inf
for k in range(26):
    b=a[k]
    temp=-math.inf
    nb=len(b)
    if nb==0:
        continue
    if nb==1:
        temp=max(b[0]+1,n-b[0])
    else:
        for i,j in enumerate(b):
            if i==0:
                temp=max(temp,b[i]+1)
                temp=max(temp,b[i+1]-b[i])
            elif i==nb-1:
                temp=max(temp,b[i]-b[i-1])
                temp=max(temp,n-b[i])
            else:
                temp=max(temp,b[i]-b[i-1])
                temp=max(temp,b[i+1]-b[i])
    res=min(res,temp)
print(res)
