using System;

​

public class Program

{

    public static void Main()

    {

        int test1 = 1;

        int test2 = 2;

        int test3 = 3;

        int test4 = 12;

        int test5 = 13;

        int test6 = 103;

        int test7 = 1412412;

        int test8 = 12313;

        Console.WriteLine(ToPlacement(test1));

        Console.WriteLine(ToPlacement(test2));

        Console.WriteLine(ToPlacement(test3));

        Console.WriteLine(ToPlacement(test4));

        Console.WriteLine(ToPlacement(test5));

        Console.WriteLine(ToPlacement(test6));

        Console.WriteLine(ToPlacement(test7));

        Console.WriteLine(ToPlacement(test8));

        string ToPlacement(int num)

        {

            string lastDigit = num.ToString().Substring(num.ToString().Length - 1, 1);

            if (num % 100 == 12 || num % 100 == 13)

                return num.ToString() + "th";

            else

                return (lastDigit)switch

                {

                "1" => num.ToString() + "st", "2" => num.ToString() + "nd", "3" => num.ToString() + "rd", _ => num.ToString() + "th", }; // woah theres a tidy up button that made this one line xd

        }

    }

}