ch5 ex4 contacts

response = 1
contacts = []
while response != 0:
    response = int(input("Enter:\n1. to add\n2. to remove\n3. to print\n0. to exit\n"))
    if response == 1:
        name = input("Enter the name you want to add: ")
        if name in contacts:
            print("Name already present in contacts")
        else:
            contacts.append(name)
            print("Name added successfully")
    elif response == 2:
        name = input("Enter the name you want to remove: ")
        if name not in contacts:
            print("Name not present in contacts")
        else:
            contacts.remove(name)
            print("Name removed successfully")
    elif response == 3:
        contacts.sort()
        for name in contacts:
            print(name)
        print()