#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pb push_back
const int maxn = 1e5 + 10;
const int mod = 1e9 + 7;
int n, L[maxn], dp[maxn], h[maxn], w[maxn], ps[maxn];
int mul(int a, int b) {
return (1ll * a * b) % mod;
}
int C(int a) {
return 1ll * a * (a + 1) / 2 % mod;
}
signed main() {
cin >> n;
for (int i = 1; i <= n; i++)
cin >> h[i];
for (int i = 1; i <= n; i++)
cin >> w[i];
stack<int> st;
for (int i = 1; i <= n; i++) {
while (st.size() && h[st.top()] >= h[i])
st.pop();
L[i] = 0;
if (!st.empty())
L[i] = st.top();
st.push(i);
}
for (int i = 1; i <= n; i++) {
ps[i] = ps[i - 1] + w[i];
ps[i] %= mod;
}
ll ans = 0;
dp[0] = 0;
// cout << L[1] << '\n';
for (int i = 1; i <= n; i++) {
ll ln = (ps[i] - ps[L[i]] + mod) % mod;
ll l1 = (ln - w[i] + mod) % mod;
dp[i] = dp[L[i]] + mul(ln, C(h[i]));
dp[i] %= mod;
ll a = 0;
a += mul(w[i], mul(C(h[i]), l1));
a %= mod;
a += mul(C(w[i]), C(h[i]));
a %= mod;
ll b = mul(dp[L[i]], w[i]);
ans = ans + a + b;
ans %= mod;
}
// cout << '\n';
cout << ans << '\n';
}
