#include<iostream>
#include<vector>

using namespace std;

int main( void )
{
    int N;
    cin >> N;
    vector<bool> is_dirty( N + 1, 0 );
    int cur = 0;
    is_dirty[0] = 1;
    int M, A, B;

    cin >> M;
    while( cur < N )
    {
        cin >> A;
        cur += A;
        is_dirty[cur] = 1;
    }

    cin >> M;
    while( cur > 0 )
    {
        cin >> B;
        cur -= B;
        is_dirty[cur] = 1;
    }

    int ans = 0;
    for( int i = 0; i <= N; i++ )
    {
        ans += !is_dirty[i];
    }

    cout << ans << endl;

    return 0;
}