using System;

​

public class Program

{

    public static void Main()

    {

        int cost = 30;

        int BuildingRebuildCostPenaltyMultiplier = 80;

        int BuildingRebuildCostPenaltyMultiplierMultiplier = 30;

        int buildingDestoryedCount = 1;

        double totalCost =  cost * (BuildingRebuildCostPenaltyMultiplier / 10

                                * Math.Pow(BuildingRebuildCostPenaltyMultiplierMultiplier / 10, buildingDestoryedCount - 1));

        Console.WriteLine(totalCost);

    }

}