task 23 py

def f(start_pos, current_pos):
    if start_pos == current_pos:
        return 1
    if start_pos > current_pos:
        return 0
    k = f(start_pos, current_pos-1)
    k += f(start_pos, current_pos-2)
    if current_pos % 2 == 0:
        k += f(start_pos, current_pos//2)
    return k


print(f(3, 10)*f(10, 12))