The school has decided to create three new math groups and equip classrooms with new desks. There is a place for exactly two people at every desk. So, no more than two students can occupy a desk. We know how many students are in each group. Output the smallest number of desks that the school needs to buy. Each group sits in a separate classroom.
Input data format
The program receives three non-negative integers — the number of students in each of three classes (the numbers do not exceed 1000).
