import java.util.*;
import java.lang.*;
import java.io.*;
import java.math.*;
import java.text.*;

class Triangles
{
	public static double square(double num){ return num*num; }
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner in = new Scanner(System.in);
		double s[] = new double[3];		
		for(int i = 0; i < 3; i++)
			s[i] = in.nextDouble();
		java.util.Arrays.sort(s);
		if(s[0] + s[1] <= s[2]){
			System.out.println("The triangle doesn't exist.");
		}
		else{
			double cosValue = Math.cos((square(s[0]) + square(s[1]) + square(s[2]))/(2*s[0]*s[1]));	
			if(cosValue > 0) System.out.println("The triangle is acute.");
			else System.out.println("The triangle is not acute.");
		}
	}
}