using System;

public class Program

{

    public static void Main()

    {

        int a,b,c,d=0,x=0,y=0,z=0;

        for (int i=1;i<=30;i++)

        {   

            Console.Write("grade1:");

            a=int.Parse(Console.ReadLine());

            Console.Write("grade2:");

            b=int.Parse(Console.ReadLine());

            Console.Write("grade3:");

            c=int.Parse(Console.ReadLine());

            if (a==-1&&b==-1&&c==-1)

                x++;

            else if (a!=-1&&b!=-1&&c!=-1)

                y++;

            else if (a==-1&&b!=-1&&c!=-1||a!=-1&&b==-1&&c!=-1||a!=-1&&b!=-1&&c==-1)

                z++;

            else 

                d++;                        

            }

        Console.WriteLine("three homeworks:"+y);

        Console.WriteLine("two homeworks:"+z);

        Console.WriteLine("one homework:"+d);

        Console.WriteLine("zero homeworks:"+x);

    }

}