class Car:
    def __init__(self, make, model):
        self.running = False
        self.make = make
        self.model = model
        
    def make_and_model(self):
        return ' '.join((self.make, self.model))

    def start(self):
        if not self.running:
            print "Started the car."
            self.running = True
        else:
            print "The car is already running."
            
    def stop(self):
        if self.running:
            print "Stopped the car."
            self.running = False
        else:
            print "The car isn't running."
            
            
            
class Tank(Car):
    def __init__(self, make, model):
        Car.__init__(self, make, model)
        self.bullets = 3
    
    def shoot(self):
        if self.bullets > 0:
            self.bullets -= 1
            print "Shot a bullet."
        else:
            print "You're out of bullets."