using System;
using System.Collections.Generic;

public class Program
{
    public static IEnumerable<int[]> Combinations(int m, int n)
    {
            int[] result = new int[m];
            Stack<int> stack = new Stack<int>();
            stack.Push(0);

            while (stack.Count > 0)
           {
                int index = stack.Count - 1;
                int value = stack.Pop();

                while (value < n)
               {
                    result[index++] = ++value;
                    stack.Push(value);

                    if (index == m)
                    {
                        yield return result;
                        break;
                    }
                }
            }
    }

    static void Main()
    {
        foreach (int[] c in Combinations(3, 5))
        {
            Console.WriteLine(string.Join(",", c));
            Console.WriteLine();
        }
    }
}