#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,m,n) for(int i=m; i<n; ++i)
#define repl(i,m,n) for(ll i=m; i<n; ++i)

int main(){
    int N, L1;
    cin >> N >> L1;

    vector<int> A(L1);
    for(int &a : A) cin >> a;

    int L2;
    cin >> L2;

    vector<int> B(L2);
    for(int &b : B) cin >> b;

    vector<bool> clean(N+1, true);
    clean[0] = clean[N] = false;
    int S = 0;
    rep(i, 0, L1){
        S += A[i];
        clean[S] = false;
    }
    int T = N;
    rep(i, 0, L2){
        T -= B[i];
        clean[T] = false;
    }

    int ans = 0;
    rep(i, 0, N+1){
        if(clean[i]) ans++;
    }
    cout << ans << endl;

    return 0;
}