#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
#define popcountll __builtin_popcountll
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
ll gcd(ll a, ll b){
	if(a==0) return b;
	if(b==0) return a;
	if(a<0) a=-a;
	if(b<0) b=-b;
	const int s=__builtin_ctzll(a|b);
	a>>=__builtin_ctzll(a);
	while(b){
		b>>=__builtin_ctzll(b);
		if(a>b) swap(a, b);
		b-=a;
	}
	return a<<s;
}
int main()
{
	int n, m; cin>>n>>m;
	ll a[2020], b[2020];
	for(int i=0; i<n; i++) cin>>a[i];
	for(int i=0; i<m; i++) cin>>b[i];
	const ll MOD=1e9+7;
	ll 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)+gcd(a[i], b[j])-1+2*a[i];
			ans%=MOD;
		}
	}
	cout<<ans<<endl;
	return 0;
}