#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pll pair<ll,ll>
#define fs first
#define sc second
const ll mxn = 1e5+10;
const ll mod = 1e9+7;
ll pw(ll a,ll b){
ll re = 1;
while(b){
if(b&1)re = re*a%mod;
a = a*a%mod;
b>>=1;
}
return re;
}
ll inv(ll k){
return pw(k,mod-2);
}
ll mad(ll a,ll b){
a += b;
if(a>=mod)a -= mod;
return a;
}
ll mub(ll a,ll b){
a = a+mod-b;
if(a>=mod)a -= mod;
return a;
}
ll mul(ll a,ll b){
return (a%mod)*(b%mod)%mod;
}
ll dp[mxn];
deque<pll> dq;
ll h[mxn],w[mxn],preh[mxn],prew[mxn];
int main(){
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
ll n;
cin>>n;
for(int i = 1;i<=n;i++){
cin>>h[i];
preh[i] = mad(preh[i-1],h[i]);
}
for(int i = 1;i<=n;i++){
cin>>w[i];
prew[i] = mad(prew[i-1],w[i]);
}
// cout<<mul(h[n]+1,h[n])*mul(prew[n],prew[n]+1)%mod*inv(4)%mod;return 0;
dq.push_back({0,0});
ll ah = 0;
ll area = 0;
for(ll i = 1;i<=n;i++){
dp[i] = mul(w[i]+1,h[i]+1)*mul(w[i],h[i])%mod*inv(4)%mod;
while(dq.back().fs>h[i]){
ah = mub(ah,mul(dq.back().fs,mul(dq.back().fs,mub(prew[dq.back().sc],prew[dq[dq.size()-2].sc]))));
// ah = mub(ah,mul(dq.back().fs,mul(dq.back().fs,mub(prew[i-1],prew[dq.back().sc-1]))));
area = mub(area,mul(dq.back().fs,mub(prew[dq.back().sc],prew[dq[dq.size()-2].sc])));
// area = mub(area,mul(dq.back().fs,mub(prew[i-1],prew[dq.back().sc-1])));
auto pre = dq.back();
dq.pop_back();
ah = mad(ah,mul(h[i],mul(h[i],mub(prew[pre.sc],prew[dq.back().sc]))));
area = mad(area,mul(h[i],mub(prew[pre.sc],prew[dq.back().sc])));
// ah = mad(ah,mul(h[i],mul(mub(prew[i-1],prew[pre.sc-1]),h[i])));
// area = mad(area,mul(h[i],mub(prew[i-1],prew[pre.sc-1])));
}
// dp[i] = mad(dp[i],mul(mul(w[i],ah),inv(2)));
dp[i] = mad(dp[i],mul(mub(ah,area)*inv(2)%mod,w[i]));
dp[i] = mad(dp[i],mul(area,w[i]));
// cout<<i<<":"<<ah<<' '<<area<<' '<<dp[i]<<endl;
// for(auto &j:dq)cout<<j.sc<<' ';cout<<endl;
ah = mad(ah,mul(h[i],mul(h[i],w[i])));
area = mad(area,mul(h[i],w[i]));
dq.push_back({h[i],i});
}
ll total = 0;
for(int i = 1;i<=n;i++)total = mad(total,dp[i]);
cout<<total;
}
/*
3
1 2 1
1 1 1
5
1 2 3 2 1
1 1 1 1 1
2
1 2
1 2
5
1 2 1 2 1
1 1 1 1 1
*/
