using System;

public class Program

{

 public static void Main()

 {

 int i, j;

 i = 0;

 j = 0;

 for (i = 1; i <= 5; i++)

 {

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

 {

 Console.Write(j);

 }

 Console.Write("\n");

 }

}

}

​