#include <cstdio>
#include <stack>
#include <vector>
#define X first
#define Y second
#define pb push_back
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int MOD = 1e9 + 7;
const int N = 1e5 + 10;
inline int add(int a, int b) {
return ((ll) a + b + MOD) % MOD;
}
inline int mult(int a, int b) {
return (ll) a * b % MOD;
}
inline int frac(int a) {
return ((ll) a * (a + 1) / 2) % MOD;
}
int n, H[N], W[N];
int sol, sum;
stack<pii> stog;
int product(int h, int w) {
return mult(w, frac(h));
}
int calc(int h, int w) {
return mult(frac(w), frac(h));
}
int _calc(int h, int w1, int w2) {
return mult(mult(w1, w2), frac(h));
}
int main() {
scanf("%d", &n);
for(int i = 0; i < n; i++) scanf("%d", H + i);
for(int i = 0; i < n; i++) scanf("%d", W + i);
for(int i = 0; i < n; i++) {
sol = add(sol, calc(H[i], W[i])); //printf("+= %d\n", calc(H[i], W[i]));
int _w = 0;
while(!stog.empty() && stog.top().X >= H[i]) {
int h = stog.top().X;
int w = stog.top().Y;
sum = add(sum, -product(h, w));
_w = add(_w, w);
stog.pop();
}
sol = add(sol, mult(sum, W[i]));
sol = add(sol, _calc(H[i], _w, W[i]));
_w = add(W[i], _w);
stog.push({H[i], _w});
sum = add(sum, product(H[i], _w));
}
printf("%d\n", sol);
return 0;
}
