#include <bits/stdc++.h>
using namespace std;
#define int long long
#define sp << ' ' <<
#define nl << '\n'
const int LIM = 1e5+1, MOD = 1e9+7;
int n, h[LIM], w[LIM], e[LIM], dp[LIM];
int nC2(int x){ return ((x * (x-1)) / 2) % MOD; }
int cnt(int x, int y){
return (nC2(x+1) * nC2(y+1)) % MOD;
}
int find(int u){
return e[u] < 0 ? u : e[u] = find(e[u]);
}
void unite(int u, int v, int currH){
u = find(u), v = find(v);
if(u != v){
if(e[u] > e[v]) swap(u, v);
dp[u] += cnt(w[u], h[u]) - cnt(w[u], currH);
dp[v] += cnt(w[v], h[v]) - cnt(w[v], currH);
e[u] += e[v], e[v] = u;
(w[u] += w[v]) %= MOD;
(dp[u] += dp[v]) %= MOD;
h[u] = currH;
}
}
signed main(){
cin.tie(0)->sync_with_stdio(0);
cin >> n;
for(int i=1; i<=n; ++i) cin >> h[i];
for(int i=1; i<=n; ++i) cin >> w[i];
int a[n]; iota(a, a+n, 1);
sort(a, a+n, [&](int &x, int &y){
return h[x] > h[y];
});
fill(e, e+LIM, -1);
for(int &i : a){
if(i != 1 && h[find(i-1)] >= h[i]) unite(i, i-1, h[i]);
if(i != n && h[find(i+1)] >= h[i]) unite(i, i+1, h[i]);
}
int r = find(1);
dp[r] += cnt(w[r], h[r]);
dp[r] %= MOD;
cout << (dp[r] + MOD) % MOD;
}
