#include <iostream>
#include <vector>
using namespace std;
int main(){
	int Nw;
	cin >> Nw;
	vector<int> W(Nw);
	for (int i = 0; i < Nw; i++){
		cin >> W[i];
	}
	int Nb;
	cin >> Nb;
	vector<int> B(Nb);
	for (int i = 0; i < Nb; i++){
		cin >> B[i];
	}
	vector<int> Wcnt(21, 0);
	for (int i = 0; i < Nw; i++){
		Wcnt[W[i]]++;
	}
	vector<int> Bcnt(21, 0);
	for (int i = 0; i < Nb; i++){
		Bcnt[B[i]]++;
	}
	vector<int> dpW(21, 0);
	vector<int> dpB(21, 0);
	for (int i = 1; i <= 20; i++){
		dpW[i] = dpW[i - 1];
		dpB[i] = dpB[i - 1];
		if (Wcnt[i] > 0){
			dpW[i] = max(dpW[i], dpB[i - 1] + 1);
		}
		if (Bcnt[i] > 0){
			dpB[i] = max(dpB[i], dpW[i - 1] + 1);
		}
	}
	cout << max(dpW[20], dpB[20]) << endl;
}