#include <iostream>
using namespace std;

long long gcd(long long a, long long b) {
    if (a < 0) a = -a;
    if (b < 0) b = -b;
    if (a < b) swap(a, b);
    while (b > 0) { long long t = a; a = b; b = t % b; }
    return a;
}

int main() {
    int n, m; cin >> n >> m;
    long long  a[n], b[m];
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < m; i++) cin >> b[i];
    const int M = 1000000007;
    long long ans = 0;
    for (int i = 0; i < n; i++) {
        if (a[i] == 0) continue;
        for (int j = 0; j < m; j++)
            ans += (a[i] + 1) * (b[j] + 1) % M + gcd(a[i], b[j]) - 2 * b[j] - 1;
    }
    cout << ans % M << endl;
}