using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        Console.WriteLine(countDigit(3313,3));

        Console.WriteLine(countDigit(3,3));

        Console.WriteLine(countDigit(272247,7));

    }

    public static int countDigit(int n, int digit)

    {

        if( n < 0)

            return -1;

        int count= 0;

        while(n > 0)

        {

            int r = n % 10;

            if( r == digit)

                count++;

            n = n / 10;

        }

        return count;

    }

}