using System;

​

public class Program

{

    public static void Main()

    {

        int num, num2 = 0, count = 0;

        while (count < 3)

        {

            Console.WriteLine("enter your grade: ");

            num = int.Parse(Console.ReadLine());

            if (num > 54 && num % 10 == 0)

                num2++;

            count++;

​

        }

​

        Console.WriteLine(num2);

    }

}