// CF template, version 3.0
#include <bits/stdc++.h>
using namespace std;
#define improvePerformance ios_base::sync_with_stdio(false); cin.tie(0)
#define getTest int t; cin >> t
#define eachTest for (int _var=0;_var<t;_var++)
#define get(name) int (name); cin >> (name)
#define out(o) cout << (o)
#define getList(cnt, name) vector<int> (name); for (int _=0;_<(cnt);_++) { get(a); (name).push_back(a); }
#define sortl(name) sort((name).begin(), (name).end())
#define rev(name) reverse((name).begin(), (name).end())
#define forto(name, var) for (int (var) = 0; (var) < (name); (var)++)
#define decision(b) if (b){out("YES");}else{out("NO");}
#define int long long int
template <typename T, typename I>
struct segtree {
int n;
vector<T> tree;
vector<I> initial;
T id;
segtree(int i_n, vector<I> i_initial, T i_id): n(i_n), initial(i_initial), id(i_id) {
tree.resize(4 * n);
}
T conquer(T left, T right) {
// write your conquer function
}
T value(I inp) {
// write your value function
}
void build(int v, int l, int r) {
if (l == r) tree[v] = value(initial[l]);
else {
int middle = (l + r) / 2;
build(2 * v, l, middle);
build(2 * v + 1, middle + 1, r);
tree[v] = conquer(tree[2 * v], tree[2 * v + 1]);
}
}
void upd(int v, int l, int r, int i, I x) {
if (l == r) tree[v] = value(x);
else {
int middle = (l + r) / 2;
if (middle >= i) upd(2 * v, l, middle, i, x);
else upd(2 * v + 1, middle + 1, r, i, x);
tree[v] = conquer(tree[2 * v], tree[2 * v + 1]);
}
}
T query(int v, int l, int r, int ql, int qr) {
if (ql <= l && r <= qr) return tree[v];
else if (r < ql || qr < l) return id;
int middle = (l + r) / 2;
T left = query(2 * v, l, middle, ql, qr);
T right = query(2 * v + 1, middle + 1, r, ql, qr);
return conquer(left, right);
}
};
// vector<int>
int mod = 1e9 + 7;
signed main() {
improvePerformance;
//getTest;
//eachTest {
get(n);
getList(n, H);
getList(n, W);
int ans = 0;
vector<int> dp(n); // sum of all subarrays ending at the end of the i-th range
vector<int> pref(n);
int width = 0;
stack<pair<int, int>> st;
forto(n, i) {
int x = H[i];
int y = W[i];
while (!st.empty() && st.top().first > x) {
st.pop();
}
int prev = st.empty()? 0: pref[st.top().second];
int val = x * (x + 1) / 2 % mod;
int thisone = (width - prev + mod) % mod * val % mod;
int orthisone = thisone;
int before = (st.empty()? 0: dp[st.top().second]);
thisone = (thisone + before) % mod;
int thisdp = (y * val + thisone) % mod;
dp[i] = thisdp;
ans = (ans + dp[i]) % mod;
int extra = y * (y - 1) / 2 % mod;
int extratot = extra * val % mod;
extratot = (extratot + (y - 1) * orthisone) % mod;
extratot = (extratot + (y - 1) * before) % mod;
ans = (ans + extratot) % mod;
width = (width + y) % mod;
pref[i] = width;
st.push({x, i});
}
out(ans);
//}
}
