#include <bits/stdc++.h> 

using i64 = long long; 
using u64 = unsigned long long; 
using u32 = unsigned; 

using u128 = unsigned __int128; 
using i128 = __int128; 

constexpr int mod = 1e9 + 7;

void solve() {
	int N, M; std::cin >> N >> M;
	std::vector<int> A(N), B(M);
	for(int& x : A) std::cin >> x;
	for(int& x : B) std::cin >> x;

	i64 ans = 0;	
	for(int i = 0; i < N; i ++) {
		for(int j = 0; j < M; j ++) {
			ans = (ans + A[i] - B[j]) % mod;
			ans = (ans + 1LL * A[i] * B[j] ) % mod;
			ans = (ans + std::gcd(A[i], B[j])) % mod;
		}
	}
	
	std::cout << ans;
} 

int main() { 
	std::ios::sync_with_stdio(false); 
	std::cin.tie(nullptr); 

	int T = 1; 
	//std::cin >> T; 

	while (T--) { 
		solve(); 
	} 
	return 0; 
}