# No.110 しましまピラミッド
def main():
    N = int(input())
    A = sorted(map(int, input().split()))
    M = int(input())
    B = sorted(map(int, input().split()))
    lim = 20  # 1 ≤ A𝑖, B𝑖 ≤ 20
    # dp[current color][height] := optimum length
    dp = [[0] * (lim + 1) for _ in range(2)]
    for i in range(1, lim + 1):
        if i in A:
            dp[0][i] = max(dp[1][:i]) + 1
        if i in B:
            dp[1][i] = max(dp[0][:i]) + 1
    ans = max(max(dp[0]), max(dp[1]))
    print(ans)


if __name__ == "__main__":
    main()