#include <iostream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstdlib>
#include <cassert>
#include <vector>
#include <list>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <bitset>
#include <string>
#include <algorithm>
#include <utility>
#define llint long long
#define inf 1e18
#define rep(x, s, t) for(llint (x) = (s); (x) < (t); (x)++)
#define Rep(x, s, t) for(llint (x) = (s); (x) <= (t); (x)++)
#define chmin(x, y) (x) = min((x), (y))
#define chmax(x, y) (x) = max((x), (y))
#define mod 1000000007

using namespace std;
typedef pair<llint, llint> P;

llint n, m;
llint a[2005], b[2005];

llint gcd(llint a, llint b)
{
	if(b == 0) return a;
	return gcd(b, a%b);
}

int main(void)
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	cin >> n >> m;
	for(int i = 1; i <= n; i++) cin >> a[i];
	for(int i = 1; i <= m; i++) cin >> b[i];
	
	llint ans = 0;
	for(int i = 1 ; i <= n; i++){
		if(a[i] == 0) continue;
		for(int j = 1; j <= m; j++){
			llint g = gcd(a[i], b[j]);
			llint B = g + a[i] + b[j];
			llint I = (a[i]*b[j] + 2 - B) / 2;
			ans += (I + g + a[i] - 1) % mod, ans %= mod;
		}
	}
	ans *= 2, ans %= mod;
	cout << ans << endl;
	
	return 0;
}