#include<iostream>
using namespace std;
int main()
{
	int num1, num2,num3;
	cout << "enter 3 numbers:" << endl;
	cin >> num1 >> num2 >> num3;

	if ((num1 + num2 > num3) && (num2 + num3 > num1) && (num3 + num1 > num2)) {//checks if it can be a triangle.

		if (num1 == num2 && num1 == num3 && num2 == num3) { //checks if the triangle can be equilateral.
			cout << "equilateral triangle" << endl;

		}
		 else
			if (num1 == num2 || num1 == num3||num2==num3) {//checks if it's a isosceles triangle.
				cout << "isosceles triangle" << endl;
			}
		 else
			if (num1 != num2 && num1 != num3 && num2 != num3) {//checks if it's a scalene triangle.
				cout << "scalene triangle" << endl;

			}

	}
	else
		cout << "cannot form a triangle" << endl;



//	system("pause");
	return 0;
}