#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using db = long double;
using llu = unsigned long long;
using str = string;
// pairs
using pii = pair<int,int>;
using pll = pair<ll,ll>;
using pdb = pair<db,db>;
#define mp make_pair
#define fr first
#define sc second
#define tcT template<class T
#define tcTU tcT, class U
tcT> using V = vector<T>;
tcT, size_t SZ> using AR = array<T,SZ>;
using vi = V<int>;
using vb = V<bool>;
using vl = V<ll>;
using vd = V<db>;
using vs = V<str>;
using vpi = V<pii>;
using vpl = V<pll>;
using vpd = V<pdb>;
#define ms0(x) memset(x , 0, sizeof(x))
#define sz(x) int((x).size())
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define rall(x) x.rbegin(), x.rend()
#define sor(x) sort(all(x))
#define rsz resize
#define ins insert
#define pb push_back
#define eb emplace_back
#define ft front()
#define bk back()
#define lb lower_bound
#define ub upper_bound
tcT> int lwb(V<T>& a, const T& b) { return int(lb(all(a),b)-bg(a)); }
tcT> int upb(V<T>& a, const T& b) { return int(ub(all(a),b)-bg(a)); }
// loops
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define rep(a) F0R(_,a)
#define each(a,x) for (auto& a: x)
const int MOD = (int)2019201949; // 998244353;
const int MX = (int)2e5+5;
const ll BIG = 1e18;
const db PI = acos((db)-1);
using ld = long double;
const int dx[4] = {0,1,0,-1};
const int dy[4] = {-1,0,1,0};
void setIO(string name = "") {
cin.tie(0)->sync_with_stdio(0);
if (sz(name)) {
freopen((name + ".in").c_str(), "r", stdin);
freopen((name + ".out").c_str(), "w", stdout);
}
}
template <int MOD=1'000'000'007>
struct Modular {
int value;
static const int MOD_value = MOD;
Modular(long long v = 0) { value = v % MOD; if (value < 0) value += MOD;}
Modular(long long a, long long b) : value(0){ *this += a; *this /= b;}
Modular& operator+=(Modular const& b) {value += b.value; if (value >= MOD) value -= MOD; return *this;}
Modular& operator-=(Modular const& b) {value -= b.value; if (value < 0) value += MOD;return *this;}
Modular& operator*=(Modular const& b) {value = (long long)value * b.value % MOD;return *this;}
friend Modular mexp(Modular a, long long e) {
Modular res = 1; while (e) { if (e&1) res *= a; a *= a; e >>= 1; }
return res;
}
friend Modular inverse(Modular a) { return mexp(a, MOD - 2); }
Modular& operator/=(Modular const& b) { return *this *= inverse(b); }
friend Modular operator+(Modular a, Modular const b) { return a += b; }
friend Modular operator-(Modular a, Modular const b) { return a -= b; }
friend Modular operator-(Modular const a) { return 0 - a; }
friend Modular operator*(Modular a, Modular const b) { return a *= b; }
friend Modular operator/(Modular a, Modular const b) { return a /= b; }
friend std::ostream& operator<<(std::ostream& os, Modular const& a) {return os << a.value;}
friend bool operator==(Modular const& a, Modular const& b) {return a.value == b.value;}
friend bool operator!=(Modular const& a, Modular const& b) {return a.value != b.value;}
friend bool operator>=(Modular const& a, Modular const& b) {return a.value >= b.value;}
friend bool operator>(Modular const& a, Modular const& b) {return a.value >= b.value;}
};
const int mod = (int)1e9 + 7;
ll inv2 = 500000004;
#define xx first
#define yy sc
void solve(){
int n;
cin>>n;
vector<ll> h(n+1,0), w(n+1,0);
for(int i=0;i<n;++i) cin>>h[i];
for(int i=0;i<n;++i) cin>>w[i];
n++;
vector<pair<ll,ll>> t;
t.push_back({0,0});
ll ans=0;
for(int i=0;i<n;++i) {
ll w_len=0;
while(t.back().xx>h[i]) {
ll h_prev=max(h[i],t[(int)t.size()-2].xx);
ll h_diff=t.back().xx-h_prev;
w_len=(w_len+t.back().yy)%mod;
t.pop_back();
ans+=(h_diff*(h_diff+1)%mod*inv2%mod+h_diff*h_prev%mod)*(w_len*(w_len+1)%mod*inv2%mod)%mod;
ans%=mod;
}
if(t.back().xx==h[i]) {
t.back().yy=(t.back().yy+w_len+w[i])%mod;
}else {
t.push_back({h[i], (w_len+w[i])%mod});
}
}
cout<<ans;
}
int main() {
setIO("");
// freopen("input.txt", "r", stdin);
// // freopen("output.txt", "w", stdout);
solve();
return 0;
}
