alcohol_level_string = input("Enter blood alcohol level (mg/100ml): ")
alcohol_level = float(alcohol_level_string)
age_string = input("Enter age in years: ")
age = float(age_string)
if age >= 20 and alcohol_level < 30 :
    print("You're allowed to drive")
elif ((alcohol_level <= 49 or alcohol_level <= 30) and age > 19):
    print("You're legally allowed to drive, but please don't")
elif age < 20 or alcohol_level >= 50 :
    print ("You're not allowed to drive")