It's Christmas Eve, and Anna and Elsa are making dinner for their friends! They want to surprise everybody with their favourite holiday dish: Christmas pudding, but they don't know how many to make. Anna knows that of their friends will eat Christmas puddings, while Elsa knows that the rest will eat Christmas puddings. Can you help them?
The first and only line will contain integers and .
Output the number of Christmas puddings Anna and Elsa need to make.
10 4 2 3