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

namespace NumbersOfTriangles
{
    class NumbersOfTriangles
    {
        class Triangles
        {
            static int a, b, c, d;
            int TriangleSides = 3;
            int[] Values = { a, b, c, d };

            public Triangles()
            {
                Console.WriteLine("Podaj długość boku a: ");
                a = Int32.Parse(Console.ReadLine());

                Console.WriteLine("Podaj długość boku b: ");
                b = Int32.Parse(Console.ReadLine());

                Console.WriteLine("Podaj długość boku c: ");
                c = Int32.Parse(Console.ReadLine());

                Console.WriteLine("Podaj długość boku d: ");
                d = Int32.Parse(Console.ReadLine());
            }

            public int AllTriangles()
            {
                int n = Values.Length;
                int k = TriangleSides;
                int nk = n - k;

                int factorialN= 1;
                int factorialK= 1;
                int factorialNK=1;

                int FactorialN()
                {

                    for (int i = 1; i <= n; i++)
                    {
                        factorialN *= i;
                    }

                    return factorialN;
                }

                 int FactorialK()
                {
                    for (int i = 1; i <= k; i++)
                    {
                        factorialK *= i;
                    }

                    return factorialK;
                }

                int FactorialNK()
                {
                    for (int i = 1; i <= nk; i++)
                    {
                        factorialNK *= i;
                    }

                    return factorialNK;
                }

                int FN = FactorialN();
                int FK = FactorialK();
                int FnK = FactorialNK();

                int NumberOfTriangles = FN / FK * FnK;
                return NumberOfTriangles;
            }

            public int[,] DivisionOfTriangles()
            {
                int[,] Triangles = new int[AllTriangles(), TriangleSides];
                int x = 0;

                for (int row = 0; row < Triangles.GetLength(0); row++)
                {
                    for (int column = 0; column < Triangles.GetLength(1); column++)
                    {
                        if (column + x == 4)
                        {
                            x = -2;
                        }
                        if (row == 3 && column == 0)
                        {
                            x = 3;
                        }
                        else if (row == 3 && column != 0)
                        {
                            x = -1;
                        }

                        Triangles[row,column] = Values[column + x];
                    }

                    x++;

                }

                return Triangles; //jak zwrócić wypełnioną tablicę?
            }

            static void Main(string[] args)
            {
                Triangles Triangles = new Triangles();
                Console.WriteLine(Triangles.DivisionOfTriangles()); //podupione łubudu

                Console.ReadLine();
            }
        }
    }
}