One weekend, there were 98 pizzas ordered for the sophomore dorm. That weekend 19 customers ordered
their pizza with just pepperoni, 16 customers ordered their pizza with just sausage, 20 ordered theirs with just
onions, 15 ordered theirs with pepperoni and sausage, 9 ordered theirs with sausage and onions, 17 ordered
theirs with pepperoni and onions, and 2 ordered theirs with all three items. How many customers ordered
their pizza with pepperoni or sausage (or both)?