#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define int long long
#define inf 1000000007
#define LINF 100000000000000007LL
#define ll long long
using namespace std;
signed main(){
	int n;
	cin>>n;
	vector<int> a(n),b(n);
	vector< pair<int,int> > p;
	for(int i=0;i<n;i++){
		cin>>a[i];
		p.pb( mp(a[i],0) );
	}
	for(int i=0;i<n;i++){
		cin>>b[i];
		p.pb( mp(b[i],1) );
	}
	sort( p.begin(), p.end() );
	int ac = 0, bc = 0;
	int ans = 1;
	for(int i=0;i<p.size();i++){
		int tp = p[i].second;
		if( tp == 1 ){
			if( bc == 0 ){
				ac++;
			}
			else{
				ans *= bc;
				ans %= inf;
				bc--;
			}
		}
		else{
			if( ac == 0 ){
				bc++;
			}
			else{
				ans *= ac;
				ans %= inf;
				ac--;
			}
		}
	}
	cout<<ans<<endl;
	return 0;
}