#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define pb push_back

const ll mod = 1e9 + 7;

void solve() {
    ll n;
    cin >> n;
    vector<ll> height(n, 0ll);
    vector<ll> width(n, 0ll);
    for(ll &x : height) cin >> x;
    for(ll &x : width) cin >> x;
    ll overall_width = 0;
    ll current_width = 0;
    ll ans = 0;
    height.pb(1ll);
    width.pb(0ll);
    for(ll i = 0; i <= n; ++i) {
        overall_width += width[i];
        overall_width %= mod;
        if(height[i] == 2) {
            current_width += width[i];
            current_width %= mod;
        } else {
            ans += (current_width * (current_width + 1)) / 2;
            ans %= mod;
            current_width = 0;
        }
    }
    ans *= 2;
    ans %= mod;
    ans += (overall_width * (overall_width + 1)) / 2;
    ans %= mod;
    cout << ans << "\n";
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    solve();
    return 0;
}