#include<iostream>
#include<cstdio>
using namespace std;
int n,m,r,a[105],b[105];
int main(){
	freopen("killer.in","r",stdin);
	freopen("killer.out","w",stdout);
	cin>>n>>m>>r;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	for(int i=1;i<=m;i++){
		cin>>b[i];
	}
	for(int i=1;i<=m;i++){
		bool flag=true;
		for(int j=1;j<=n;j++){
			if(b[i]%a[j]!=0){flag=false;}
		}
		if(flag){cout<<i<<" ";return 0;}
	}
	bool notf=false;
	if(!notf){
		for(int i=1;i<=m;i++){
			int cnt=0;
			for(int j=1;j<=n;j++){
				if(b[i]%a[j]==0){cnt++;}
			}
			if(cnt>=r){cout<<i<<" ";notf=true;}
		}
	}
	if(!notf){cout<<0;}
	return 0;
}