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.");
		}
	}
}

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