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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N; cin >> N;
    vector<bool> W(20),B(20);
    while(N--){
        int w; cin >> w; w--;
        W.at(w) = true;
    }
    cin >> N;
    while(N--){
        int b; cin >> b; b--;
        B.at(b) = true;
    }

    vector<int> dpW(20,-1000),dpB(20,-1000);
    for(int i=0; i<20; i++){
        if(W.at(i)) dpW.at(i) = 1;
        if(B.at(i)) dpB.at(i) = 1;
    }
    int answer = 0;
    for(int i=19; i>=0; i--){
        if(W.at(i)){
            int now = -1000;
            for(int k=i+1; k<20; k++) now = max(now,dpB.at(k));
            if(now != -1000) dpW.at(i) = now+1;
        }
        if(B.at(i)){
            int now = -1000;
            for(int k=i+1; k<20; k++) now = max(now,dpW.at(k));
            if(now != -1000) dpB.at(i) = now+1;
        }
        answer = max(answer,dpW.at(i));
        answer = max(answer,dpB.at(i));
    }
    cout << answer << endl;
}