#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e5 + 5;
const int MOD = 1e9 + 7;
const int inv2 = 500000004;
int n;
int h[N], w[N], ps[N], dp[N];
int l[N];
void Solve() {
cin >> n;
for (int i = 1; i <= n; i++) cin >> h[i];
for (int i = 1; i <= n; i++) {
cin >> w[i];
ps[i] = ps[i - 1] + w[i];
}
long long ans = 0;
stack<int> st;
for (int i = 1; i <= n; i++) {
while (!st.empty() && h[st.top()] >= h[i]) {
st.pop();
}
l[i] = st.empty() ? 0 : st.top();
st.push(i);
int sh = h[i] % MOD * (h[i] % MOD + 1) % MOD * inv2 % MOD;
int sw = w[i] % MOD * (w[i] % MOD + 1) % MOD * inv2 % MOD;
ans = (ans + sh * sw) % MOD;
int W1 = (ps[i - 1] - ps[l[i]]);
W1 = (W1 % MOD + MOD) % MOD;
int S1 = (dp[l[i]] + W1 * sh) % MOD;
ans = (ans + S1 * w[i]) % MOD;
int W2 = (ps[i] - ps[l[i]]);
W2 = (W2 % MOD + MOD) % MOD;
dp[i] = (dp[l[i]] + W2 * sh) % MOD;
}
cout << ans;
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
Solve();
return 0;
}
