import java.util.StringTokenizer;
import java.io.*;  // for I/O

public class TriAreaCalculatorEmpty
{

	static BufferedReader keyboard = new BufferedReader 
										    	(new InputStreamReader (System.in));
	
	public static void Header()
	{
		//Use System.out to print an introduction as to the purpose of this 
		//program. Ask the user for three numbers separated by spaces, 
		//followed by enter.
	}
	
	public static double ComputeS(double a, double b, double c)
	{
		//Set a variable s to be the sum of a, b, and c, all divided by 2.
		
		return s;
	}
	
	public static double ComputeArea(double a, double b, double c, double s)
	{
		//The area is the square root of the product of s, s-a, s-b, and s-c.
		
		return area;
	}
	
	public static void Report(double a, double b, double c, double result)
	{
		System.out.print("A triangle with sides length " + a + ", " + b
							+ ", and " + c + "\nhas an area of " + result + ".\n"); 
	}
	
	public static void main (String[] args) throws IOException
	{
		double a, b, c, s, area;
		StringTokenizer tokenizer;
		
		Header();
		tokenizer = new StringTokenizer(keyboard.readLine());
		
		//Look in Tokenize.java for how to set the variables
		a = ;
		b = ;
		c = ;
		
		s = ComputeS(a,b,c);
		area = ComputeArea(a,b,c,s);
		
		Report(a,b,c,area);
		
		
	}  
}