def n_p(x, y):
    if x > y:
        return 0
    if x == y:
        return 1
    if x == 9:
        return n_p(x*2, y)
    if x < y:
        return n_p(x+1, y) + n_p(x*2, y)
print(n_p(1, 10)*n_p(10, 20)+n_p(1, 9)*n_p(9, 20))