using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;


class Program

{
    static int f(uint x) {
        return (int)x*(int)x;
    }
    static void change (uint x, uint y, uint z, out uint a1, out uint a2,out uint a3){
        a1 = x > y ? (y > z ? z : y) : (x > z ? z : x);
        a2 = x > y ? (x < z ? x : (z < y ? y : z)) : (y < z ? y : (x > z ? x : y));
        a3 = x > y ? (x > z ? x : z) : (y > z ? y : z);
    }
    static bool check(uint a, uint b, uint c) {
        bool check_answer = (a + b) > c & (a + c) > b & (b + c) > a ? true : false;
        return check_answer;
    }
    static string get_answer(uint big_side, uint mid_side, uint sm_side) {
        string answer;
        return answer = f(big_side) >= f(mid_side) + f(sm_side) ? (f(big_side) > f(mid_side) + f(sm_side) ? "obtuse" : "right") : ("acute");
    }
    static void Main()
    {
        uint side_1, side_2, side_3, sm_side, mid_side, big_side;
        string input_1, input_2, input_3;
        input_1 = Console.ReadLine();
        if (!uint.TryParse(input_1, out side_1))
        {
            Console.WriteLine("wrong");
            Console.ReadLine();
        }
        else
        {
            input_2 = Console.ReadLine();
            if (!uint.TryParse(input_2, out side_2))
            {
                Console.WriteLine("wrong");
                Console.ReadLine();
            }
            else
            {
                input_3 = Console.ReadLine();
                if (!uint.TryParse(input_3, out side_3))
                {
                    Console.WriteLine("wrong");
                    Console.ReadLine();
                }

                else
                {
                    change(side_1, side_2, side_3, out sm_side, out mid_side, out big_side);
                    Console.WriteLine(check(side_1, side_2, side_3) ? get_answer(big_side, mid_side, sm_side) : "impossible");
                    Console.ReadLine();
                }
            }
        }
        }
}