StudentCables - corrected

using System;


class StudentCables
{
    static void Main()
    {
        int cables = int.Parse(Console.ReadLine());

    // all variables can be int
        int sumOfCables = 0;

        // stores how many cables we actually use after losing the short ones
        int used = cables;

        for (int i = 0; i < cables; i++)
        {
            int cableLength = int.Parse(Console.ReadLine());
            string measure = Console.ReadLine();
            if (measure == "meters")
            {
                cableLength = cableLength * 100;
            }

            if (cableLength < 20 && measure != "meters")
            {
                cableLength = 0;
                used--;
            }

          sumOfCables = sumOfCables + cableLength;
        }

    // the amount we cut depends on the number of cables actually used
        sumOfCables = sumOfCables - (used - 1) * 3;

        int countCables = sumOfCables / 504;
        int remainder = sumOfCables % 504; // simpler way to get the remainder

        Console.WriteLine(countCables);
        Console.WriteLine(remainder);
    }
}