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

    public class TriAreaCalculator
   {
   
          
       public static void main (String[] args) throws IOException
      {
         double a, b, c, s, area;
         //StringTokenizer tokenizer;
      
      
      //In a dialog box, ask the user to enter numbers.
         //System.out.println("Please enter three numbers, separated by spaces.");
  
  String input =  JOptionPane.showInputDialog (null, "Enter an expression," +
													" separated by spaces.", 
            									"A simple addition calculator", 
            									 JOptionPane.QUESTION_MESSAGE);  
		
		
		
      //tokenize the user input.
         StringTokenizer tokenizer = new StringTokenizer(input);
      
      //parse the user input.
         a = Double.parseDouble(tokenizer.nextToken());
         //b = Double.parseDouble(tokenizer.nextToken());
			String op = tokenizer.nextToken();
         c = Double.parseDouble(tokenizer.nextToken());
      
      //This is where we might check and see whether the three numbers can be the 
      //sides of a triangle.  IF they cannot be, then we should inform the user, ELSE
      //we should perform the computation.
      
      
      //These two method calls can simply be replaced by the code from those methods.   
      //s = ComputeS(a,b,c);
      //area = ComputeArea(a,b,c,s);
        // s = (a + b + c)/2;
        // area = Math.sqrt(s*(s-a)*(s-b)*(s-c));
			//double sum = a + b + c;
			//area = a + b + c;
      
      
      //we construct the string that we want to output.		
        // String message = "A triangle with sides length " + a + ", " + b
        //    			+ ", and " + c + "\nhas an area of " + area + ".\n";
		  
		  String message = "The sum of " + a + " and " + c + " is " + (a + c);
      
      //show the message string.
        JOptionPane.showMessageDialog (null, message, "A simple addition calculator",
                                       JOptionPane.ERROR_MESSAGE);
													
			
      
      }  
   }