#include <bits/stdc++.h>
using namespace std;
#define el '\n'
#define int long long
#define fi first
#define se second
#define sz(x) (int)(x).size()
const int maxn=1e5+5,mod=1e9+7;
int n,h[maxn],w[maxn]; bool checksub2=1,checksub3=1,checksub4=1,checksub5=1,checksub6=1;
namespace sub2{
int res;
void solve(){
for (int l=1;l<=n;l++){
int mn=1e18;
for (int r=l;r<=n;r++){
mn=min(mn,h[r]);
int tmp1=mn,tmp2=mn+1;
if (tmp1%2==0) tmp1/=2; else tmp2/=2;
int c=tmp1*tmp2%mod;
res=(res+c)%mod;
}
}
cout<<res;
}
}
namespace sub3{
int tmp1,tmp2,add,res;
void solve(){
int M=0;
for(int i=1;i<=n;i++) M+=w[i];
tmp1=M,tmp2=M+1;
if (tmp1%2==0) tmp1/=2; else tmp2/=2;
int sum=(tmp1%mod)*(tmp2%mod)%mod;
int cnt=0,cur=0;
for (int i=1;i<=n;i++){
if(h[i]==2) cur+=w[i];
else{
tmp1=cur,tmp2=cur+1;
if (tmp1%2==0) tmp1/=2; else tmp2/=2;
add=(tmp1%mod)*(tmp2%mod)%mod; cnt=(cnt+add)%mod;
cur=0;
}
}
if (cur){
tmp1=cur,tmp2=cur+1;
if (tmp1%2==0) tmp1/=2; else tmp2/=2;
add=(tmp1%mod)*(tmp2%mod)%mod; cnt=(cnt+add)%mod;
}
res=(sum+2*cnt)%mod;
cout<<res;
}
}
namespace sub4{
void solve(){
int H=h[1],M=0;
for (int i=1;i<=n;i++) M+=w[i];
int tx1=M,tx2=M+1,ty1=H,ty2=H+1;
if (tx1%2==0) tx1/=2; else tx2/=2;
if (ty1%2==0) ty1/=2; else ty2/=2;
int tmp1=(tx1%mod)*(tx2%mod)%mod,tmp2=(ty1%mod)*(ty2%mod)%mod;
cout<<(tmp1*tmp2)%mod;
}
}
namespace sub5{
int suf[maxn],tmp1,tmp2,res;
void solve(){
for (int i=n;i>=1;i--) suf[i]=suf[i+1]+w[i];
for (int i=1;i<=n;i++){
int wi=w[i],hi=h[i];
tmp1=wi,tmp2=wi+1;
if (tmp1%2==0) tmp1/=2; else tmp2/=2;
int val1=(tmp1%mod)*(tmp2%mod)%mod;
int val2=(wi%mod)*(suf[i+1]%mod)%mod;
int sum=(val1+val2)%mod;
tmp1=hi,tmp2=hi+1;
if (tmp1%2==0) tmp1/=2; else tmp2/=2;
int cnt=(tmp1%mod)*(tmp2%mod)%mod;
res=(res+sum*cnt)%mod;
}
cout<<res;
}
}
namespace sub6{
int pre[maxn],res,tmp1,tmp2;
void solve(){
for (int i=1;i<=n;i++) pre[i]=pre[i-1]+w[i];
for (int l=1;l<=n;l++){
int mn=1e18;
for (int r=l;r<=n;r++){
mn=min(mn,h[r]);
int W=pre[r]-pre[l-1];
tmp1=W,tmp2=W+1;
if (tmp1%2==0) tmp1/=2; else tmp2/=2;
int A=(tmp1%mod)*(tmp2%mod)%mod;
tmp1=mn,tmp2=mn+1;
if (tmp1%2==0) tmp1/=2; else tmp2/=2;
int B=(tmp1%mod)*(tmp2%mod)%mod;
res=(res+A*B)%mod;
}
}
cout<<res;
}
}
namespace sub7{
int res,W,M,tmp1,tmp2,val1,val2;
void solve(){
///Anh Khang béo vãi lồn
}
}
signed main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin>>n;
for (int i=1;i<=n;i++) cin>>h[i];
for (int i=1;i<=n;i++) cin>>w[i];
for (int i=1;i<=n;i++){
if (w[i]!=1) checksub2=0;
if (!(h[i]==1||h[i]==2)) checksub3=0;
if (i>1&&h[i]!=h[1]) checksub4=0;
if (i<n&&h[i]>h[i+1]) checksub5=0;
}
if (n>50) checksub2=0; if (n>1000) checksub6=0;
if (checksub2) sub2::solve();
else if (checksub3) sub3::solve();
else if (checksub4) sub4::solve();
else if (checksub5) sub5::solve();
else if (checksub6) sub6::solve();
else sub7::solve();
}
