#include <iostream>
#include <algorithm>
using namespace std;
/*
Sort all the rectangles by height.
Repeat:
Look at the tallest rectangle with height H and width W.
Let h be the larger height among its neighbors.
Count all fancy rectangles whose top edge is in the range [h+1, H] = (W*(W+1)/2) * ((H-h)*(H-h+1)/2)
Reduce the height of the tallest rectangle to h and merge it with the right neighbors
Reverse the above algorithm
Solution
Repeat:
Look at the lowest rectangle with height H
Find the rectangles to the left and right closest to this rectangle which have height strictly less than H.
(Sparse table + Binary search)
Let the total width bounded between (not inside either rectangle) these rectangles be W
Add (Hchoose2 + Hchoose1) * (Wchoose2 + Wchoose1)
*/
long long N;
long long h[100002][18];
long long w[100001];
long long l2[100002];
long long rect[100001];
long long mod = 1e9 + 7;
long long hmin(long long l, long long r)
{
return min(h[l][l2[r-l+1]], h[r - (1LL << l2[r-l+1]) + 1][l2[r-l+1]]);
}
int main()
{
cin >> N;
h[0][0] = h[N+1][0] = 0;
for(long long i = 1; i <= N; i++)
{
cin >> h[i][0];
}
for(long long j = 1; j <= 17; j++)
{
for(long long i = 1; i + (1LL << j) - 1 <= N; i++)
{
h[i][j] = min(h[i][j-1], h[i + (1LL << (j-1))][j-1]);
}
}
w[0] = 0;
for(long long i = 1; i <= N; i++)
{
cin >> w[i];
w[i] = (w[i] + w[i-1]) % mod;
}
l2[1] = 0;
for(long long i = 2; i <= N; i++) l2[i] = l2[i/2] + 1;
for(long long i = 0; i <= N; i++) rect[i] = i;
sort(rect+1, rect+N+1,
[] (long long a, long long b)
{
if(h[a][0] == h[b][0]) return a < b;
return h[a][0] < h[b][0];
}
);
//for(int i = 1; i <= N; i++) cout << rect[i] << ' ';
//cout << '\n';
long long res = 0;
long long curr, L, R;
long long x, y, m;
for(long long i = 1; i <= N; i++)
{
curr = rect[i];
if(h[curr][0] == h[rect[i-1]][0] && hmin(rect[i-1], curr) == h[curr][0]) continue;
// cout << curr << ' ' << h[curr][0] << ' ';
x = 0;
y = curr-1;
while(x != y)
{
m = (x+y)/2 + 1;
if(hmin(m, curr-1) >= h[curr][0]) y = m-1;
else x = m;
}
L = x;
//Problem is, with nodes of equal heights
x = curr+1;
y = N+1;
while(x != y)
{
m = (x+y)/2;
if(hmin(curr+1, m) >= h[curr][0]) x = m+1;
else y = m;
}
R = y;
long long y1 = h[curr][0];
//long long y2 = h[rect[i-1]][0];
long long y2 = max(h[L][0], h[R][0]);
long long x = w[R-1] - w[L];
res = (res + (((x*(x+1))/2)%mod) * (( mod + (((y1*(y1+1))/2)%mod) - (((y2*(y2+1))/2)%mod) ) % mod)) % mod;
//cout << res << '\n';
}
cout << res << '\n';
}
