#include <iostream>
#include <vector>
using namespace std;

int main()
{
    int N, M;
    cin >> N >> M;
    vector<int> U(N + 1, 0);
    vector<int> T(M + 1, 0);
    for (int i = 1; i <= N; i++)
    {
        cin >> U[i];
    }

    for (int i = 1; i <= M; i++)
    {
        cin >> T[i];
    }

    vector<vector<int>> dp(M + 1, vector<int>(1000 * 100 + 1, 0));
    dp[0][0] = 1;
    for (int i = 1; i <= M; i++)
    {
        for (int j = 0; j <= 1000 * 100; j++)
        {
            if (j >= T[i])
            {
                dp[i][j] = max(dp[i - 1][j], dp[i - 1][j - T[i]]);
            }
            else
            {
                dp[i][j] = dp[i - 1][j];
            }
        }
    }

    vector<bool> check(200001, false);
    for (int i = 1; i <= N; i++)
    {
        for (int j = 0; j <= 1000 * 100; j++)
        {
            if (dp[M][j] == 1)
            {
                check[U[i] + j] = true;
            }
        }
    }

    int ans = 0;
    for (int i = 1; i <= 200000; i++)
    {
        if (check[i] == true)
        {
            ans++;
        }
    }
    cout << ans << "\n";

    return 0;
}