#include <iostream>
#include <string>
#include <vector>

int main()
{
    int n, m, as = 0, a;
    std::cin >> n >> m;
    std::vector<bool> ans(n);

    for(int i = 0; i < m; i++)
    {
        std::cin >> a;
        as += a;
        ans[as] = true;
    }
    as = n;

    std::cin >> m;
    for(int i = 0; i < m; i++)
    {
        std::cin >> a;
        as -= a;
        ans[as] = true;
    }

    int ansn = 0;
    for(int i = 0; i < n; i++)
    {
        if(!ans[i])
            ansn++;
    }
    std::cout << ansn << std::endl;
    return 0;
}