import java.util.Scanner;
public class Triangle{
    public static void main(String[] args){
        Scanner sc= new Scanner(System.in);
        double s1=sc.nextDouble();
        double s2=sc.nextDouble();
        double s3=sc.nextDouble();
        if(s1+s2<=s3){
            System.out.println("Invalid triangle");
        }
        else{
            System.out.println(tri(s1,s2,s3));
        }
    }
    static void tri(double a,double b,double c){
        if(a==b&&b==c){
            System.out.println("equilateral");
        }
        
        if(a==b||b==c||a==c){
            System.out.println("isosceles");
        }
        System.out.println("scalene");

    }
}