#include <bits/stdc++.h>
using namespace std;
#define dprint(v) cerr << #v"=" << v << endl //;)
#define forr(i,a,b) for(int i=(a); i<(b); i++)
#define forn(i,n) forr(i,0,n)
#define dforn(i,n) for(int i=n-1; i>=0; i--)
#define forall(it,v) for(auto it=v.begin();it!=v.end();++it)
#define sz(c) ((int)c.size())
#define zero(v) memset(v, 0, sizeof(v))
#define pb push_back
#define fst first
#define snd second
typedef long long ll;
typedef pair<int,int> ii;

const int MAXN=100100;
const ll MOD=1e9+7;
int n, p[MAXN], v[MAXN];

int main() {
    ios::sync_with_stdio(0);
    while(cin >> n){
        forn(i,n) cin >> p[i];
        sort(p,p+n);
        zero(v);
        forn(_,n) { int c; cin >> c;
            int idx = upper_bound(p,p+n,c)-p;
            if (idx) v[idx-1]++;
        }
        int av = 0;
        ll p = 1;
        dforn(i,n) {
            av += v[i];
            p = (p*av) % MOD;
            av--;
        }
        cout << p << endl;
    }
    return 0;
}