Python script to calculate the cost of a single pizza order, where the order may contain one or more pizzas.

Ask the user the size of the pizza they want - small pizzas cost $10, medium pizzas cost $12 and large pizzas cost $14.

Ask the user how many toppings they want (valid answers are between 1 and 6) - the first three toppings are free, any toppings above that cost an additional dollar per topping.

Once you have those details, ask the user if they'd like to add another pizza to the order - if so you go again from asking the size.

Once the user says they don't want to add any more pizzas to the order then display the total amount due.