Time Limit: 1 second
Memory Limit: 256 megabytes
Jzzhu has a big rectangular chocolate bar that consists of n × m unit squares. He wants to cut this bar exactly k times. Each cut must meet the following requirements:
The picture below shows a possible way to cut a 5 × 6 chocolate for 5 times.
Imagine Jzzhu have made k cuts and the big chocolate is splitted into several pieces. Consider the smallest (by area) piece of the chocolate, Jzzhu wants this piece to be as large as possible. What is the maximum possible area of smallest piece he can get with exactly k cuts? The area of a chocolate piece is the number of unit squares in it.
Output a single integer representing the answer. If it is impossible to cut the big chocolate k times, print -1.