#include <iostream>
using namespace std;
const int MAXN = 100000;
const int MOD = 1000000007;
const int INV2 = (MOD + 1) / 2;
int h[MAXN + 2], w[MAXN + 2], l[MAXN + 1], r[MAXN + 1], stiva[MAXN + 1];
long long spart[MAXN + 1];
int gauss(int n) {
return 1LL * n * (n + 1) / 2 % MOD;
}
void addSelf(int &a, int b) {
a += b;
if(a >= MOD) {
a -= MOD;
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
for(int i = 1; i <= n; i++) {
cin >> h[i];
}
for(int i = 1; i <= n; i++) {
cin >> w[i];
spart[i] = spart[i - 1] + w[i];
}
int sp = 1;
h[0] = 0;
stiva[0] = 0;
for(int i = 1; i <= n; i++) {
while(sp > 0 && h[stiva[sp - 1]] >= h[i]) {
sp--;
}
l[i] = stiva[sp - 1];
stiva[sp++] = i;
}
sp = 1;
h[n + 1] = 0;
stiva[0] = n + 1;
for(int i = n; i >= 1; i--) {
while(sp > 0 && h[stiva[sp - 1]] > h[i]) {
sp--;
}
r[i] = stiva[sp - 1];
stiva[sp++] = i;
}
int answer = 0;
for(int i = 1; i <= n; i++) {
int sum_left = (spart[i - 1] - spart[l[i]]) % MOD;
int sum_right = (spart[r[i] - 1] - spart[i]) % MOD;
int cnt = 0;
cnt = (cnt + 1LL * sum_left * sum_right) % MOD;
cnt = (cnt + 1LL * w[i] * (w[i] + 1) / 2) % MOD;
cnt = (cnt + 1LL * sum_left * w[i]) % MOD;
cnt = (cnt + 1LL * sum_right * w[i]) % MOD;
answer = (answer + 1LL * cnt * gauss(h[i])) % MOD;
}
cout << answer << "\n";
return 0;
}
