Count Empty Cells

Given a wall with m rows and n columns, you are required to cover as many cells as possible using canvases of size $1 \times 2$ or $2 \times 1$. Each canvas covers exactly two adjacent cells and cannot overlap. The task is to determine the number of cells that remain empty after placing the canvases optimally. Note that the number of empty cells is given by the formula $$(m \times n) \mod 2,$$ since if the total number of cells is odd, one cell will remain uncovered.

inputFormat

The input consists of two integers m and n separated by whitespace, representing the number of rows and columns of the wall, respectively.

outputFormat

Output a single integer representing the number of empty cells remaining after the canvases are placed optimally.

3 5

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