import java.util.Scanner;

/**
 * Program to classify triangles. You enter the lengths of the sides, and
 * the program tells you whether the triangle is equilateral, scalene, or isosceles.
 * For a refresher on what these terms mean, see
 * <a href="http://en.wikipedia.org/wiki/Triangle#Types_of_triangles">Wikipedia</a>.
 * 
 * <p>The program also detects if the specified triangle is impossible under a
 * Euclidean geometry.
 * 
 * <p>Idea for extension, if you want to try something: make the program detect
 * right triangles. Note that a right triangle can be either isosceles or scalene!
 * 
 * @author pollen
 */
public class TriangleClassification {
    public static void main(String[] args) {
        
        Scanner in = new Scanner(System.in);
        
        // Collect the lengths of the three ties. Tell the user to separate
        // the values by spaces so that in.nextDouble can distinguish them.
        System.out.println("Enter the lengths of the three sides, separated by spaces: ");
        double a = in.nextDouble();
        double b = in.nextDouble();
        double c = in.nextDouble();
        
        // First check if it is possible for a triangle to be formed of these three
        // sides.
        if ((a + b <= c) || (b + c <= a) || (a + c <= b)) {
            System.out.println("No such triangle exists, at least in Euclidean space.");
            
        } else {
            // Perform basic equality tests once and for all.
            boolean aEqualsB = (a == b);
            boolean bEqualsC = (b == c);
            boolean aEqualsC = (a == c);
            
            if (aEqualsB && bEqualsC && aEqualsC) {
                System.out.println("This triangle is equilateral.");
                
            } else if (aEqualsB || bEqualsC || aEqualsC) {
                System.out.println("This triangle is isosceles.");
                
            } else {
                System.out.println("This triangle is scalene.");
            }
        }
    }
}