using System;

public class Program

{

    public static void Main()

    {

        // reducing percentage

        var step = 5;

        //max. HP percentage

        decimal max = 100;

        // first percentage of reduce

        decimal percentOfMax = (max / 100) * step;

        //how much percent of HP remains

        decimal remains = 52;

        int i = 0;

        for (i = 0; i < 10; i++)

        {

            // reduce by step

            max = max - percentOfMax;

            remains = remains - percentOfMax;

            //calculate new reduction percentage because base HP changed by first reduction

            percentOfMax = (max / 100) * step;

            // reduce again because brall hits twice

            max = max - percentOfMax;

            remains = remains - percentOfMax;

​

            if (remains < 0)

            {

                Console.Write("Boss killed after " + i + " Brall hits");

                return;

            }

        }

​

        Console.Write("Not killed. " + remains + " % of HP remains");

    }

}