def main():

    # input from keyboard
    # simple if then else comparison
    # booleans and conditions 
    
    print()
    name = input("What is your name? ")
    print("Hello " + name + ", nice to meet you!")
    age = int(input("How old are you? "))
    yesnomaybe = input("OK " + name + ", did you know that 2 times " + str(age) + " is " + str(age*2) + "? (enter yes/no/maybe) ")
    if yesnomaybe == "yes":
        print("Because you are smart!!")
    elif yesnomaybe == "maybe":
        print("Well, now you know for sure!")
    else:
        print("Well, we learn something new every day, right?")

    friends = list()
    add_another_friend = True
    
    while add_another_friend:
        # this means - list is not empty
        if friends: 
            friend = input("Tell me the name of another friend: ")
        else:
            friend = input("Tell me the name of a friend: ")
        friends.append(friend)
        print("Ok, these are your friends:")
        count = 0 
        for friend in friends:
            count += 1
            print("  Friend #" + str(count) + " of " + name + ": " + friend)

        while True:  
            answer = input("Do you want to add another friend? ")
        
            stop = answer == 'stop' or answer == 'no' or answer == 'quit'        
            add_another_friend = answer in ['ok', 'fine', 'yes', 'true', 'roger', 'okay', 'sure']
            
            if stop or add_another_friend:
                break 
            else:
                print("Hmm, not sure I understood you. Please tell me again:")
                
    print("OK, until next time!")

main()