import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int Nw = sc.nextInt();
    int[] w = new int[Nw];
    for(int i = 0; i < Nw; i++) {
      w[i] = sc.nextInt();
    }
    int Nb = sc.nextInt();
    int[] b = new int[Nb];
    for(int i = 0; i < Nb; i++) {
      b[i] = sc.nextInt();
    }
    Arrays.sort(w);
    Arrays.sort(b);
    int[] lowW = new int[21];
    int[] lowB = new int[21];
    lowW[0] = -1;
    lowW[1] = -1;
    lowB[0] = -1;
    lowB[1] = -1;
    for(int i = 2; i < 21; i++) {
      boolean flg = true;
      for(int j = Nw - 1; j >= 0; j--) {
        if(w[j] < i) {
          lowW[i] = j;
          flg = false;
          break;
        }
      }
      if(flg) lowW[i] = -1;
      flg = true;
      for(int j = Nb - 1; j >= 0; j--) {
        if(b[j] < i) {
          lowB[i] = j;
          flg = false;
          break;
        }        
      }
      if(flg) lowB[i] = -1;
    }
    // dpw[i]はw[i]を一番下とした時のピラミッドの高さの最大値
    // dpb[i]はb[i]を一番下とした時のピラミッドの高さの最大値
    int[] dpw = new int[Nw];
    int[] dpb = new int[Nb];
    dpw[0] = 1;
    dpb[0] = 1;
    if(lowB[w[0]] >= 0) dpw[0] = 2;
    if(lowW[b[0]] >= 0) dpb[0] = 2;
    int indexw = 1;
    int indexb = 1;
    for(int i = 0; i < Nw + Nb - 2; i++) {
      if(indexw < Nw) {
        if(lowB[w[indexw]] == -1) {
          dpw[indexw] = 1;
          indexw++;
        } else if(lowB[w[indexw]]  < indexb) {
          dpw[indexw] = 1 + dpb[lowB[w[indexw]]];
          indexw++;
        }
      }
      if(indexb < Nb) {
        if(lowW[b[indexb]] == -1) {
          dpb[indexb] = 1;
          indexb++;
        } else if(lowW[b[indexb]]  < indexw) {
          dpb[indexb] = 1 + dpw[lowW[b[indexb]]];
          indexb++;
        }        
      }
    }
    int ans = Math.max(dpw[Nw - 1], dpb[Nb - 1]);
    System.out.println(ans);
  }
}