#include <bits/stdc++.h>
using namespace std;
typedef long long un;
typedef vector<un> vuc;
typedef pair<un, un> pun;
#define REP(i, a, b) for (un i = (un)a; i < (un)b; i++)
#define REPR(i, a, b) for (un i = ((un)b)-1; i >= (un)a; i--)
#define FEAC(i, a) for (auto&& i : a)
#define vec vector
#define ALL(x) (x).begin(), (x).end()
#define DEB(x) cerr << #x << " = " << (x) << endl;
constexpr un MOD = 1e9 + 7;
vuc walls;
un M;
un i2w(un i){
return walls[i];
}
un w2i(un w){
return lower_bound(ALL(walls), w) - walls.begin();
}
int main(){
un N;
cin >> N;
vuc A(N);
vuc B(N);
set<un> walls_set;
REP(i, 0, N){
cin >> A[i];
walls_set.insert(A[i]);
}
REP(i, 0, N){
cin >> B[i];
walls_set.insert(B[i]);
}
walls_set.insert(1);
FEAC(w, walls_set){
walls.push_back(w);
}
M = walls.size();
vuc vody(M, 0);
vuc vysky(M, 0);
vysky[0] = 1;
REP(e, 0, N){
vuc pref_vysky(M, 0);
pref_vysky[M-1] = vysky[M-1];
REPR(i, 0, M-1){
pref_vysky[i] = pref_vysky[i+1] + vysky[i];
pref_vysky[i] %= MOD;
}
vuc new_vysky(M, 0);
vuc new_vody(M, 0);
FEAC(val, vuc({w2i(A[e]), w2i(B[e])})){
un counter = 0;
REP(i, 0, val){
counter += vysky[i];
counter %= MOD;
}
new_vysky[val] += counter;
new_vysky[val] %= MOD;
REP(i, val, M){
new_vysky[i] += vysky[i];
new_vysky[i] %= MOD;
}
REP(i, 0, val){
new_vody[i] += vody[val];
new_vody[i] %= MOD;
}
un last_zvys = 0;
REP(i, val, M){
new_vody[i] += vody[i] + (i2w(i) - i2w(val)) * pref_vysky[i] + last_zvys;
new_vody[i] %= MOD;
last_zvys += (i2w(i) - i2w(val)) * vysky[i];
last_zvys %= MOD;
}
}
vysky = new_vysky;
vody = new_vody;
}
cout << vody[0] << endl;
}
