#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef pair<ll, ll> pll;
const ll MOD=1e9+7;
vll h, w, subsum;
ll ans=0;
void solve(int l, int r){
if(r<=l+1) return;
int m=(l+r)/2;
solve(l, m);
solve(m, r);
//now solve for segments between!!
//if the h on the right side is strictly smaller:
ll mini1=MOD;
for(int i=m, j=m; j<r;){
mini1=min(mini1, h[j]);
while(i-1>=l && h[i-1]>mini1) i--;
ans+=((((subsum[m]-subsum[i]+MOD)%MOD)*(w[j]))%MOD)*((((mini1*mini1+mini1)/2)%MOD)%MOD);
ans%=MOD;
j++;
}
mini1=MOD;
for(int i=m-1, j=m-1; i>=l;){
mini1=min(mini1, h[i]);
while(j+1<r && h[j+1]>=mini1) j++;
ans+=((((subsum[j+1]-subsum[m]+MOD)%MOD)*w[i])%MOD)*(((mini1*mini1+mini1)/2)%MOD);
ans%=MOD;
i--;
}
}
int main(){
int n;
cin>>n;
h.resize(n);
w.resize(n);
subsum.assign(n+1, 0);
for(int i=0; i<n; i++) cin>>h[i];
for(int i=0; i<n; i++) cin>>w[i];
for(int i=0; i<n; i++) subsum[i+1]=(subsum[i]+w[i])%MOD;
for(int i=0; i<n; i++){
ans+=(((h[i]*h[i]+h[i])/2)%MOD)*(((w[i]*w[i]+w[i])/2)%MOD);
ans%=MOD;
}
bool works=1;
for(int i=0; i+1<n; i++) if(h[i]>h[i+1]) works=0;
if(works){
for(int i=0; i<n; i++){
ans+=((w[i]*(((h[i]*h[i]+h[i])/2)%MOD))%MOD)*(subsum[n]-subsum[i+1]+MOD);
ans%=MOD;
}}
if(!works) solve(0, n);
cout<<ans;
return 0;
}
