///*** Sown_Vipro ***///
/// ->TEAM SELECTION TEST<- ///
#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("O3")
//#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("popcnt")
#define F first
#define S second
#define pb push_back
#define pi pair<int, int>
#define pii pair<int, pair<int, int> >
#define FOR(i, a, b) for(int i = a; i <= b; ++i)
#define REP(i, a, b) for(int i = a; i >= b; --i)
#define all(s) s.begin(), s.end()
#define szz(s) int(s.size())
const string NAME = "sown";
const int N = 1e6 + 5, MAX = 1e6, MOD = 1e9 + 7;
void maxi(int &x, int y){ if(x < y) x = y; }
void mini(int &x, int y){ if(x > y) x = y; };
void add(int &x, int y){ x += y; x += MOD * (x < 0); x -= MOD * (x >= MOD); };
int n;
int h[N], w[N], s[N];
void solve(){
cin >> n;
int checksub3 = 1, checksub4 = 1;
FOR(i, 1, n){
cin >> h[i];
if(i != 1 && h[i] != h[i - 1]) checksub3 = 0;
if(i != 1 && h[i] < h[i - 1]) checksub4 = 0;
}
FOR(i, 1, n){
cin >> w[i];
s[i] = (s[i - 1] + w[i]) % MOD;
}
if(checksub3){
int A = 1ll * h[1] * (h[1] + 1) % MOD * 500000004 % MOD;
int B = 1ll * s[n] * (s[n] + 1) % MOD * 500000004 % MOD;
cout << (1ll * A * B) % MOD;
return;
}
if(checksub4){
int res = 0, f = 0;
FOR(i, 1, n){
int A = 1ll * h[i] * (h[i] + 1) % MOD * 500000004 % MOD;
int B = 1ll * w[i] * (w[i] + 1) % MOD * 500000004 % MOD;
res = (res + 1ll * A * B) % MOD;
res = (res + 1ll * f * w[i]) % MOD;
f = (f + 1ll * A * w[i]) % MOD;
}
cout << res;
return;
}
vector<int> st;
st.pb(0);
int res = 0;
FOR(i, 1, n){
while(h[st.back()] >= h[i]){
st.pop_back();
}
int j = szz(st) - 1, last = i - 1;
int A = 1ll * h[i] * (h[i] + 1) % MOD * 500000004 % MOD;
int B = 1ll * w[i] * (w[i] + 1) % MOD * 500000004 % MOD;
res = (res + 1ll * A * B) % MOD;
REP(H, h[i], 1){
while(h[st[j]] >= H) --j;
int W = (s[last] - s[st[j]] + MOD) % MOD;
// cout << i << " " << H << " " << w[i] << " " << last << " " << st[j] << " " << W << "\n";
int A = 1ll * H * (H + 1) % MOD * 500000004 % MOD;
int B = 1ll * w[i] * W % MOD;
res = (res + 1ll * A * B) % MOD;
last = st[j];
}
st.pb(i);
}
cout << res;
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
if(fopen((NAME + ".inp").c_str(), "r")){
freopen((NAME + ".inp").c_str(), "r", stdin);
freopen((NAME + ".out").c_str(), "w", stdout);
}
int t = 1;
// cin >> t;
while(t--){
solve();
}
}
