```cpp
#include<bits/stdc++.h>
using namespace std;
int n,k,b,a[1000000],ans=9999999,m=0,p=1;
bool c[1000000];
int main(){
cin>>n>>k>>b;
for(int i=1;i<=b;i++){
cin>>a[i];
}
memset(c,1,sizeof(c));
for(int i=1;i<=n;i++){
c[a[i]]=0;
}
while(k<=n){
for(int i=p+0;i<=k;i++){
if(c[i]==0) m++;
}
if(m<ans) ans=m;
k++;
p++;
m=0;
}
cout<<ans;
return 0;
}
//暴力加O2搞定
by gengxinbujianduan @ 2023-07-12 17:09:39