Employee Seating Arrangement

Given a grid with r rows and c columns, determine the maximum number of employees that can be seated such that no two employees are adjacent. Two employees are considered adjacent if they share a side or a diagonal.

This problem is equivalent to finding the maximum independent set in a grid graph. The answer can be computed based on the parity of the grid dimensions:

• If either r = 1 or c = 1, then the answer is \(\left\lfloor\frac{r \times c + 1}{2}\right\rfloor\).
• If either r or c is even, then the answer is \(\frac{r \times c}{2}\).
• If both r and c are odd, then the answer is \(\frac{r \times c}{2} + 1\).

Your task is to write a program that reads two integers from the standard input (representing r and c) and prints the maximum number of employees that can be seated according to the above rules.

inputFormat

The input consists of a single line containing two space-separated integers r and c, where r is the number of rows and c is the number of columns of the grid.

outputFormat

Output a single integer which is the maximum number of employees that can be seated such that no two employees are adjacent.

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