Problem L
Triangle Area
                                                                                    
  Per-Magnus managed to solve his addition homework thanks to you, but now he is unfortunately posed with an even greater problem.
He has been given a triangular cake by his mother, and wonders what the area of it is. It turns out Per-Magnus forgot the formula for computing it!
Per-Magnus managed to measure the base and height of the triangle with a ruler. Given this, compute the area of the triangular cake.
Input
The input consists of a single line with two integers $ 1 \le h \le 1000 $ and $1 \le b \le 1000$, the height and base of the triangle.
Output
Output a single number, the area of the triangle. Your answer must be correct within an absolute or relative error of $10^{-7}$.
| Sample Input 1 | Sample Output 1 | 
|---|---|
| 1 1 | 0.5 | 
| Sample Input 2 | Sample Output 2 | 
|---|---|
| 2 2 | 2 | 
