import java.util.*;
class Trangle{
    float s1,s2,s3;
    
    Trangle( double s1, double s2, double s3 ){
        
        this.s1 = s1;
        this.s2 = s2;
        this.s3 = s3;
    }
    boolean isValidTrangle(){
        return s1+ s2> s3 &&s2 + s3 >s2 && s1 +s3>s2;
    }
    String getType(){
        if(!isValidTrangle())
            return "Invalid trangle";
        if(s1==s2 && s2==s3)
            return "equilateral";
        if(s1==s2 || s2==s3 ||s1==s3)
            return "isosceles";
        return "scalene";   
    }
}
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        double s1 = sc.nextDouble();
        double s2 = sc.nextDouble();
        double s3 = sc.nextDouble();
        
        Trangle t = new Trangle(s1,s2,s3);
        System.out.print(t.getType());
    }
}