#include<stdio.h>

int main(){   
	float a,b,c;

	scanf("%f %f %f",&a,&b,&c);
	
	if(a==b && a==c ){printf("equilateral triangle");return 0;}
	if(a==b || a==c){printf("isoceles triangle");return 0;}
	if(a*a+b*b == c*c || a*a+c*c == b*b || b*b+c*c == a*a){printf("right-angled triangle");return 0;}
	if(a+b>c && a+c>b && b+c>a){printf("arbitrary triangle");return 0;}
	printf("It isn't triangle");
	return 0;
}