#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using P = pair<int, int>;
using mint = modint1000000007;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main()
{
    int N, M;
    cin >> N >> M;
    vector<int> A(N), B(M);
    rep(i, N) cin >> A[i];
    rep(i, M) cin >> B[i];
    mint ans = 0;
    rep(i, N)
    {
        rep(j, M)
        {
            ans += floor_sum(B[j] + 1, B[j], A[i], 0) * 2;
        }
    }
    cout << ans.val() << endl;
}