Bottle of Beer

bobotw = " bottles of beer on the wall"
bob = " bottles of beer."
take = "Take one down and pass it around, "
beer = 99

def on_wall(beer):
    while beer >= 0:
        if beer == 0:
            print("No more" + bobotw + ", no more" + bob)
            print("Go to the store and buy some more, 99" + bobotw + ".")
            return
        elif beer == 1:
            print(str(beer) + " bottle of beer on the wall, " + str(beer) + " bottle of beer.")
            beer -= 1
            print(take + "no more" + bobotw + ".")
        elif beer == 2:
            print(str(beer) + bobotw + ", " + str(beer) + bob)
            beer -= 1
            print(take + "only one bottle of beer on the wall.")
        else:
            print(str(beer) + bobotw + ", " + str(beer) + bob)
            beer -= 1
            print(take + str(beer) + bobotw + ".")

answer = input("Do you want to see the Bottles of Beer song? (y/n) : ")

if answer.lower() == "y":
    on_wall(beer)
elif answer.lower() == "n":
    print("Bollocks to ya then.")
else:
    print("It's y for yes, n for no.")