#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define pb push_back
#define int long long
#define repp(i,x,n) for(int i=x;i<=n;i++)
#define rep(i,x,n) for(int i=x;i>=n;i--)
#define r0 return 0
#define fi first
#define se second
#define liow ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define jelek cout<<"jelek"<<endl
#define pii pair<int,int>
#define all(v) v.begin(),v.end()
#define tp tuple<int,int,int>
#define fl fflush(stdout)
#define ld long double
#pragma GCC optimize ("O2")
#pragma GCC optimize ("unroll-loops")
#define pil pair<int,int>
#define p3 pair<int,pii>
#define p5 pair<int,pair<pii,pii>>
using namespace std;
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
typedef tree<pair<int,int>, null_type, less<pair<int,int>>, rb_tree_tag, tree_order_statistics_node_update> ordered_multiset;
const int mod=1e9+7;
const int SQMAX=635,INF=1e18;
//const int mod=998244353;
//const int MOD=1e6+3;
mt19937_64 rng((unsigned int) chrono::steady_clock::now().time_since_epoch().count());
pii dr[8]={{-1,0},{-1,1},{0,1},{1,1},{1,0},{1,-1},{0,-1},{-1,-1}};
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
int dxx[4]={1,1,-1,-1};
int dyy[4]={1,-1,-1,1};
int mul(int x,int y){return (x%mod*y%mod)%mod;}
int expo(int b,int e){
if(e==0) return 1;
int tmp=expo(b,e/2);
if(e%2) return mul(tmp,mul(tmp,b));
else return mul(tmp,tmp);
}
const int maxn=100005;
const int N=1e5;
pii st[4*maxn];
int h[maxn],w[maxn];
int n;
void build(int l,int r,int node){
if(l==r){
st[node]={h[l],l};
} else {
int mid=(l+r)/2;
build(l,mid,2*node);
build(mid+1,r,2*node+1);
st[node]=min(st[2*node],st[2*node+1]);
}
}
pii que(int a,int b,int l,int r,int node){
if(r<a||l>b) return {INF,INF};
else if(a<=l && r<=b) return st[node];
else {
int mid=(l+r)/2;
return min(que(a,b,l,mid,2*node),que(a,b,mid+1,r,2*node+1));
}
}
int ans=0;
int pfw[maxn];
void lio(int l,int r,int prv){
if(l>r) return;
// cout<<l<<" "<<r<<" "<<prv<<endl;
pii ah=que(l,r,1,n,1);
// cout<<ah.fi<<" "<<ah.se<<endl;
if(ah.fi!=prv){
int leb=(pfw[r]-pfw[l-1])%mod;
int x=leb%mod*(leb+1)%mod*expo(2,mod-2)%mod;
int tot=(prv+1+ah.fi)%mod*(ah.fi-prv)%mod*expo(2,mod-2)%mod;
ans=(ans+x*tot%mod)%mod;
}
lio(l,ah.se-1,ah.fi);
lio(ah.se+1,r,ah.fi);
}
void solve(){
cin>>n;
repp(i,1,4*maxn) st[i]={INF,INF};
repp(i,1,n) cin>>h[i];
repp(i,1,n){
cin>>w[i];
pfw[i]=pfw[i-1]+w[i];
}
build(1,n,1);
// jelek;
lio(1,n,0);
cout<<ans<<endl;
}
signed main(){
liow;
solve();
}
