//雪花飄飄北風嘯嘯
//天地一片蒼茫
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ii,ll>
#define fi first
#define se second
#define endl '\n'
#define debug(x) cout << #x << " is " << x << endl
#define rep(x,start,end) for(auto x=(start)-((start)>(end));x!=(end)-((start)>(end));((start)<(end)?x++:x--))
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()
#define indexed_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
//change less to less_equal for non distinct pbds, but erase will bug
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
const int MOD=1000000007;
ll fix(ll i){
i%=MOD;
if (i<0) i+=MOD;
return i;
}
ll nC2(ll i){
return i*(i+1)/2%MOD;
}
ll calc(ll lo,ll hi,ll len){
//cout<<lo<<" "<<hi<<" "<<len<<endl;
return nC2(len)*(nC2(hi)-nC2(lo))%MOD;
}
int n;
ll h[100005];
ll w[100005];
vector<int> stk;
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin>>n;
rep(x,1,n+1) cin>>h[x];
rep(x,1,n+1){
cin>>w[x];
w[x]=(w[x-1]+w[x])%MOD;
}
stk.push_back(0);
ll ans=0;
rep(x,1,n+1){
while (h[stk.back()]>h[x]){
int temp=h[stk.back()];
stk.pop_back();
ans+=calc(max(h[stk.back()],h[x]),temp,fix(w[x-1]-w[stk.back()]));
}
stk.push_back(x);
}
while (sz(stk)>1){
int temp=h[stk.back()];
stk.pop_back();
ans+=calc(h[stk.back()],temp,fix(w[n]-w[stk.back()]));
}
cout<<fix(ans)<<endl;
}
