#include <iostream>
#include <algorithm>
using namespace std;

int search(int* wp, int* bs, int limit, bool white) {
    int* p = white ? wp : bs;
    while (*p && *p >= limit) p++;
    if (*p)
        return 1 + search(white ? p : wp, white ? bs : p, *p, !white);
    else
        return 0;
}

int main() {
    int nw, nb;
    cin >> nw;
    int ws[nw+1];
    for (int i = 0; i < nw; i++) {
        int w;
        cin >> w;
        ws[i] = w;
    }
    ws[nw] = 0;
    cin >> nb;
    int bs[nb+1];
    for (int i = 0; i < nb; i++) {
        int b;
        cin >> b;
        bs[i] = b;
    }
    bs[nb] = 0;
    sort(ws,ws+nw,greater<int>{});
    sort(bs,bs+nb,greater<int>{});
    cout << max(search(ws,bs,21,true),search(ws,bs,21,false)) << endl;
    return 0;
}