#include <iostream>
#define int long long
using namespace std;
const int mod = 1000000007;
int n;
int h[101010], w[101010];
int RMQ[30][101010];
int L[101010];
int pref[101010];
int get(int l, int r) {
int x = L[r - l + 1];
int f = RMQ[x][l], s = RMQ[x][r - (1 << x) + 1];
if (h[f] <= h[s]) return f;
return s;
}
int res = 0;
void rec(int l, int r, int nowH) {
if (l > r)return;
int go = get(l, r);
int H = h[go] - nowH;
int W = pref[r] - pref[l - 1];
H %= mod; W %= mod;
res += (((((W * (W + 1)) / 2) % mod) *
(((H * (H + 1)) / 2) % mod)) % mod);
res %= mod;
res += (((((((W * (W + 1)) / 2) % mod) * H) % mod) * nowH) % mod);
res %= mod;
// cout << l << " " << r << " << " << endl;
rec(l, go - 1, h[go]); rec(go + 1, r, h[go]);
return;
}
int32_t main()
{
cin >> n;
for (int i = 1; i <= n; i++)cin >> h[i];
for (int i = 1; i <= n; i++)cin >> w[i];
for (int i = 1; i <= n; i++) {
pref[i] = pref[i - 1] + w[i];
}
L[1] = 0;
for (int i = 2; i <= n; i++) L[i] = L[i / 2] + 1;
for (int i = 1; i <= n; i++) RMQ[0][i] = i;
for (int i = 1; i <= L[n]; i++) {
for (int j = 1; j + (1 << i) - 1 <= n; j++) {
if (h[RMQ[i - 1][j]] <= h[RMQ[i - 1][j + (1 << (i - 1))]])
RMQ[i][j] = RMQ[i - 1][j];
else
RMQ[i][j] = RMQ[i - 1][j + (1 << (i - 1))];
}
}
rec(1, n, 0);
cout << res;
}
