#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pi pair<int, int>
#define vi vector<int>
#define vs vector<string>
#define vb vector<bool>
#define vpi vector<pi>
#define pb push_back
#define all(a) (a).begin(), (a).end()
const int mod = 1e9 + 7;
int md_inv_2 = 500000004;
int sm(int x)
{
return (((x * (x + 1)) % mod) * md_inv_2) % mod;
}
void solve()
{
int n;
cin >> n;
int h[n], w[n];
for (int i = 0; i < n; i++)
cin >> h[i];
int pref_w[n + 1];
pref_w[0] = 0;
for (int i = 0; i < n; i++)
{
cin >> w[i];
pref_w[i + 1] = (pref_w[i] + w[i]) % mod;
}
vpi ns;
vi nsi(n, n);
ns.pb({0, n});
for (int i = n - 1; i >= 0; i--)
{
while (ns.back().first >= h[i])
{
ns.pop_back();
}
nsi[i] = ns.back().second;
ns.pb({h[i], i});
}
int ans = 0;
vi st;
st.pb(0);
for (int i = 0; i < n; i++)
{
while (st.back() > h[i])
{
st.pop_back();
}
if (st.back() == h[i])
continue;
int w2 = (((pref_w[nsi[i]] - pref_w[i]) % mod) + mod) % mod;
ans = (ans + (sm(w2) * (((sm(h[i]) - sm(st.back())) % mod) + mod) % mod) % mod) % mod;
st.pb(h[i]);
}
cout << ans << '\n';
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
int t = 1;
// cin >> t;
while (t--)
{
solve();
}
return 0;
}
