#include <bits/stdc++.h>
#define pb push_back
#define fst first
#define snd second
#define fore(i,a,b) for(int i=a,pao=b;i<pao;++i)
#define SZ(x) ((int)x.size())
#define ALL(x) x.begin(),x.end()
#define me(a,v) memset((a),(v),sizeof(a))
#define FIN ios::sync_with_stdio(0);cin.tie(0);cout.tie(0)
using namespace std;
typedef long long ll;
typedef vector<ll> vi;
typedef pair<ll,ll> pi;
const int MOD=1e9+7,MAXN=1e5+5;
ll h[MAXN],w[MAXN],pf[MAXN];
int n;
ll mul(ll a,ll b){
return a*b%MOD;
}
void add(ll &a,ll b){
a+=b; a%=MOD;
}
ll exp(ll a,ll b){
if(b==0)return 1;
ll tmp=exp(a,b/2);
tmp=mul(tmp,tmp);
if(b%2)tmp=mul(tmp,a);
return tmp;
}
ll invMul(ll a){
return exp(a,MOD-2);
}
ll rectangle(ll a,ll b){
return (mul(a,a+1ll)*invMul(2)%MOD)*((mul(b,b+1ll))*invMul(2)%MOD)%MOD;
}
vi small(int rev){
stack<pi>s;
vi ans(n,-1);
fore(i,0,n){
while(SZ(s)&&s.top().fst+rev>h[i]){
s.pop();
}
if(SZ(s))ans[i]=s.top().snd;
s.push({h[i],i});
}
return ans;
}
ll get(int l,int r){
if(r==-1||l==n)return 0;
if(l==-1)return pf[r];
return (pf[r]-pf[l]%MOD+MOD)%MOD;
}
int main(){
cin>>n;
fore(i,0,n)cin>>h[i];
fore(i,0,n)cin>>w[i];
vi l=small(0);
reverse(h,h+n);
vi r=small(1);
reverse(h,h+n);
reverse(ALL(r));
fore(i,0,n){
r[i]=n-r[i]-1;
}
fore(i,0,n){
add(pf[i],w[i]%MOD);
if(i)add(pf[i],pf[i-1]%MOD);
}
ll ans=0;
fore(i,0,n){
int L=l[i],R=r[i];
//~ cout<<"=================="<<endl;
//~ cout<<L<<" "<<R<<endl;
ll wl=get(L,i-1),wr=get(i,R-1),wlr=0;
//~ cout<<wl<<" "<<wr<<" ";
add(wlr,((wl+wr)%MOD+w[i])%MOD);
//~ cout<<wlr<<endl;
add(ans,(rectangle(h[i],wlr)-(rectangle(h[i],wl)+rectangle(h[i],wr))%MOD+MOD)%MOD);
//~ cout<<ans<<endl;
}
cout<<ans;
}
