#include <bits/stdc++.h>
using namespace std;
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
template<int mod>istream &operator>>(istream &is,static_modint<mod> &a){long long b;is>>b;a=b;return is;}
template<int mod>ostream &operator<<(ostream &os,const static_modint<mod> &a){os<<a.val();return os;}
istream &operator>>(istream &is,modint &a){long long b;cin>>b;a=b;return is;}
ostream &operator<<(ostream &os,const modint &a){os<<a.val();return os;}
#endif
using ll=long long;
using ull=unsigned long long;
using P=pair<ll,ll>;
template<typename T>using minque=priority_queue<T,vector<T>,greater<T>>;
template<typename T>bool chmax(T &a,const T &b){return (a<b?(a=b,true):false);}
template<typename T>bool chmin(T &a,const T &b){return (a>b?(a=b,true):false);}
template<typename T1,typename T2>ostream &operator<<(ostream &os,const pair<T1,T2>&p){os<<p.first<<' '<<p.second;return os;}
template<typename T1,typename T2>istream &operator>>(istream &is,pair<T1,T2>&p){is>>p.first>>p.second;return is;}
template<typename T> ostream &operator<<(ostream &os,const vector<T> &a){cout<<'{';for(int i=0;i<a.size();i++){cout<<a[i];if(i+1!=a.size())cout<<',';};cout<<'}';return os;}
template<typename T>istream &operator>>(istream &is,vector<T> &a){for(auto &i:a)is>>i;return is;}
template<typename T1,typename T2>void operator++(pair<T1,T2>&a,int n){a.first++,a.second++;}
template<typename T1,typename T2>void operator--(pair<T1,T2>&a,int n){a.first--,a.second--;}
template<typename T>void operator++(vector<T>&a,int n){for(auto &i:a)i++;}
template<typename T>void operator--(vector<T>&a,int n){for(auto &i:a)i--;}
#define reps(i,a,n) for(int i=(a);i<(n);i++)
#define rep(i,n) reps(i,0,n)
#define all(x) x.begin(),x.end()
#define pcnt(x) __builtin_popcount(x)
ll myceil(ll a,ll b){return (a+b-1)/b;}
#ifdef LOCAL
template<typename T1,typename ...T2>
void debug(const T1& x,const T2& ...y){
  cout<<x;
  ((cout<<' '<<y),...);
  cout<<'\n';
}
#else
#define debug(...) static_cast<void>(0)
#endif
void SOLVE();
int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  #ifdef LOCAL
  clock_t start=clock();
  #endif
  int testcase=1;
  //cin>>testcase;
  for(int i=0;i<testcase;i++){
    SOLVE();
  }
  #ifdef LOCAL
  cout<<"time:";
  cout<<(clock()-start)/1000;
  cout<<"ms\n";
  #endif
}
void SOLVE(){
  int n,m;
  cin>>n>>m;
  vector<bool>a(n+1,false);
  a[0]=true;
  int cu=0;
  rep(i,m){
    int b;
    cin>>b;
    cu+=b;
    a[cu]=true;
  }
  cin>>m;
  rep(i,m){
    int b;
    cin>>b;
    cu-=b;
    a[cu]=true;
  }
  int ans=0;
  rep(i,n+1)ans+=!a[i];
  cout<<ans<<endl;
}