A Very Simple Problem

This is a very simple problem. Given three integers N, x, and M, your task is to calculate out the following value:

There are several test cases. For each case, there is a line with three integers N, x, and M, where 1 ≤ N, M ≤ 2*10⁹, and 1 ≤ x ≤ 50.
The input ends up with three negative numbers, which should not be processed as a case.

For each test case, print a line with an integer indicating the result.

100 1 10000
3 4 1000
-1 -1 -1

5050
444

2010 ACM-ICPC Multi-University Training Contest（5）——Host by BJTU