def f6(x):
  y = 0
  while (x > 0):
    x = (((x - y) - y) - 1)
    y = (y + 1)
  return y
  
def f7(x,y):
  z = 1
  if ((x>0) and (y>0)):
    z = 0
    for i in range(0,x):
      z = (z + f7(x,(y-1)))
  return z