11.Tribonacci Triangle

using System;
class Tribonacci
{
    static void Main()
    {
        long firstNumber = int.Parse(Console.ReadLine());
        long secondNumber = int.Parse(Console.ReadLine());
        long thirthNumber = int.Parse(Console.ReadLine());
        long tribonacci = 0;
        int lines = int.Parse(Console.ReadLine());

        if (lines == 2)
        {

            Console.WriteLine(firstNumber);
            Console.Write(secondNumber + " ");
            Console.WriteLine(thirthNumber);
            return;
        }
        Console.WriteLine(firstNumber);
        Console.Write(secondNumber + " ");
        Console.WriteLine(thirthNumber);

        for (int i = 3; i <= lines; i++)
        {
            for (int j = 0; j < i; j++)
            {
                tribonacci = firstNumber + secondNumber + thirthNumber;
                firstNumber = secondNumber;
                secondNumber = thirthNumber;
                thirthNumber = tribonacci;
                Console.Write(thirthNumber + " ");
            }
            Console.WriteLine();
        }
    }
}