using System;  

public class Program 

{  

    public static void Main() 

{

   int i,j,r;

   Console.WriteLine("No. of rows : ");

   r= Convert.ToInt32(Console.ReadLine());   

   for(i=1;i<=r;i++)

   {

    for(j=1;j<=i;j++)

       Console.Write("{0}",j);

    Console.Write("\n");

   }

  }

}

​