def init_glob():
  global  feet_per_meter, meter_per_foot, feet_per_mile, meters_per_kilometer, miles_per_foot, miles_per_kilometer
  feet_per_meter = 3.28
  meter_per_foot = (1.0 / feet_per_meter)
  feet_per_mile = 5280.0
  meters_per_kilometer = 1000.0
  miles_per_foot = (1.0 / feet_per_mile)
  miles_per_kilometer = (miles_per_foot * feet_per_meter * meters_per_kilometer) 
def cvt_feet_to_meters(feet):
  global meter_per_foot
  meters = feet * meter_per_foot
  return meters

def cvt_meters_to_feet(meters):
  global feet_per_meter
  feet = meters * feet_per_meter
  return feet;