#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ii pair<int,int>
typedef vector<int> vi;
#define iii tuple<int,int,int>
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef map<int,int> mii;
#ifndef debug
#define cerr if (0) cerr
#endif
int N,H[100005],W[100005];
int pref[100005], last_mins[100005];
const int mod=1e9+7;
int nc2(int n){
return ((n*(n-1))/2)%mod;
}
int rect(int h, int w){
return (nc2(h+1)*nc2(w+1))%mod;
}
int32_t main(){
cin>>N;
int last_min = -1;
for (int i=0; i<N; i++)cin>>H[i];
for (int i=0; i<N; i++){
cin>>W[i];
if (i==0) pref[i]=W[i];
else pref[i]=W[i]+pref[i-1];
last_mins[i]=last_min;
if (i>0 && H[i-1]>H[i]){
last_min = i;
}
}
int ans=0, sum=0;
stack<iii> st;
for (int i=0; i<N; i++){
ans += rect(H[i],W[i]);
ans %= mod;
int total_w = 0;
while (st.size() && get<0>(st.top()) >= H[i]){
auto [h,w,p] = st.top();
st.pop();
total_w += w;
total_w %= mod;
sum = (sum-p + mod);
sum %= mod;
}
ans += (sum*W[i])%mod;
ans %= mod;
ans += ((total_w * nc2(H[i]+1))%mod * W[i])%mod;
ans %= mod;
total_w += W[i];
total_w %= mod;
int t = total_w * nc2(H[i]+1);
t %= mod;
sum += t;
sum %= mod;
st.push({H[i], total_w, t});
}
cout<<ans;
}
