#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define fastio ios::sync_with_stdio(0); cin.tie(0);
const ll MOD = 1e9 + 7;
const ll MAXN = 500000004;
const int N = 100005;
ll h[N], w[N];
int n;
ll tri(ll x) {
x %= MOD;
return (x * (x + 1) % MOD) * MAXN % MOD;
}
ll subtask2() {
ll r = 0;
for (int i = 1; i <= n; i++) {
ll m = h[i];
for (int j = i; j <= n; j++) {
m = min(m, h[j]);
r = (r + tri(m)) % MOD;
}
}
return r;
}
ll subtask3() {
ll s = 0;
for (int i = 1; i <= n; i++) s = (s + w[i]) % MOD;
ll r = tri(s);
ll c = 0;
for (int i = 1; i <= n; i++) {
if (h[i] == 2) {
c = (c + w[i]) % MOD;
} else {
r = (r + 2 * tri(c)) % MOD;
c = 0;
}
}
r = (r + 2 * tri(c)) % MOD;
return r;
}
ll subtask4() {
ll s = 0;
for (int i = 1; i <= n; i++) s = (s + w[i]) % MOD;
return tri(h[1]) * tri(s) % MOD;
}
ll subtask5() {
ll r = 0;
vector<ll> s(n + 2, 0);
for (int i = n; i >= 1; i--) s[i] = (s[i + 1] + w[i]) % MOD;
for (int i = 1; i <= n; i++) {
ll d = (tri(h[i]) - tri(h[i - 1]) + MOD) % MOD;
r = (r + d * tri(s[i])) % MOD;
}
return r;
}
int main() {
fastio;
cin >> n;
bool b2 = true, b3 = true, b4 = true, b5 = true;
for (int i = 1; i <= n; i++) {
cin >> h[i];
if (h[i] > 50) b2 = false;
if (h[i] != 1 && h[i] != 2) b3 = false;
if (i > 1 && h[i] != h[i - 1]) b4 = false;
if (i > 1 && h[i] < h[i - 1]) b5 = false;
}
for (int i = 1; i <= n; i++) {
cin >> w[i];
if (w[i] != 1) b2 = false;
}
if (b4) cout << subtask4();
else if (b2 && n <= 50) cout << subtask2();
else if (b3) cout << subtask3();
else if (b5) cout << subtask5();
else cout << subtask4();
return (0);
}
