2016_April_24 Smart Lili

using System;

public class Program
{
    public static void Main()
    {
        int N = int.Parse(Console.ReadLine());
        var laundryPrice = double.Parse(Console.ReadLine());
        var toyPrice = int.Parse(Console.ReadLine());

        var deposit = 0;
        var moneyFromToys = 0;
        var money = 10;

        for (int i=1; i<=N;i++)
        {
            if (i%2 == 0)
            {
             deposit += money;
             deposit-=1;
             money+=10;
            }
            else
            {
                moneyFromToys+=toyPrice;
            }
        }

        var total = deposit + moneyFromToys;

        if(total>=laundryPrice)
        {
            Console.WriteLine("Yes! {0:f2}",total-laundryPrice);
        }
        else
        {
            Console.WriteLine("No! {0:f2}", laundryPrice-total);
        }

    }
}