Minimum Initial Flowers for Full Bloom

You are given a rectangular garden of size m² and n². In order for the entire garden to bloom, a minimum number of flowers must be initially planted at strategic locations. A proven observation is that planting flowers in cells corresponding to the ceiling of half of each dimension ensures full coverage. Mathematically, the number of initial flowers required is given by the formula below:

\(\lceil m/2 \rceil \times \lceil n/2 \rceil\)

Your task is to compute and output this minimum number based on the provided dimensions.

inputFormat

The input consists of a single line containing two space-separated integers \(m\) and \(n\) which represent the dimensions of the garden.

outputFormat

Output a single integer representing the minimum number of initial flowers required for the garden to fully bloom.

5 5

9