def solve(w, h, xs, ys):
    if not xs:
        return h
    if xs[0] <= w:
        return solve(w, h, xs[1:], ys)
    else:
        return solve(xs[0], h + 1, ys, xs[1:])

_ = input()
W = sorted(map(int, raw_input().strip().split()))
_ = input()
B = sorted(map(int, raw_input().strip().split()))
print(max(solve(0, 0, W, B), solve(0, 0, B, B)))