#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int ll
const int mod = 1e9 + 7, N = 1e5 + 5;
int n, h[N], w[N], sp[N];
signed main() {
cin >> n;
for (int i = 1; i <= n; i ++)
cin >> h[i];
for (int i = 1; i <= n; i ++) {
cin >> w[i];
sp[i] = (sp[i - 1] + w[i]) % mod;
}
stack<int> st, st2;
st.push(0);
st2.push(0);
long long sum = 0, rez = 0;
for (int i = 1; i <= n; i ++) {
while (h[i] <= h[st.top()]) {
sum = (sum - st2.top() + mod) % mod;
st2.pop();
st.pop();
}
sum += (sp[i - 1] - sp[st.top()] + mod) % mod * (h[i] * (h[i] + 1) / 2 % mod) % mod;
sum %= mod;
rez += 1LL * sum * w[i] % mod;
rez %= mod;
rez += w[i] * (w[i] + 1) / 2 % mod * (h[i] * (h[i] + 1) / 2 % mod) % mod;
rez %= mod;
sum += w[i] * (h[i] * (h[i] + 1) / 2 % mod) % mod;
sum %= mod;
int c_sum = (sp[i] - sp[st.top()] + mod) % mod * (h[i] * (h[i] + 1) / 2 % mod) % mod;
st2.push(c_sum);
st.push(i);
}
cout << rez << '\n';
}
