#include <bits/stdc++.h>
using namespace std;

int main() {
	int N, M1, M2;
	cin >> N >> M1;
	vector<int> v( N + 1 );
	int now = 0;
	v[now] = 1;
	for( int i = 0; i < M1; i++ ) {
		int a;
		cin >> a;
		now += a;
		v[now] = 1;
	}
	cin >> M2;
	for( int i = 0; i < M2; i++ ) {
		int b;
		cin >> b;
		now -= b;
		v[now] = 1;
	}
	int ans = 0;
	for( int i = 0; i < N + 1; i++ ) {
		if( v[i] == 0 ) ans++;
	}
	cout << ans << endl;
}