=begin
When it's spring Japanese cherries blossom, it's called "sakura" and it's admired a lot. The petals start to fall in late April.

Suppose that the falling speed of a petal is 5 centimeters per second (5 cm/s), and it takes 80 seconds for the petal to reach the ground from a certain branch.

Write a function that receives the speed (in cm/s) of a petal as input, and returns the time it takes for that petal to reach the ground from the same branch.

Notes:

The movement of the petal is quite compilcated, so in this case we can see the velocity as a constant during its falling.
Pay attention to the data types.
If the initial velocity is non-positive, the return value should be 0
=end

def sakura_fall(v)
  if v > 0 
  return (5*80.0/v)
  else
  return 0
  end
end