import java.util.Scanner;

public class FORcleverLili {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int age = Integer.parseInt(scanner.nextLine());
        double priceW = Double.parseDouble(scanner.nextLine());
        int priceT = Integer.parseInt(scanner.nextLine());


        int TOTAL = 0;
        int moneyBday = 0;
        int toys = 0;


        for (int year = 0; year < age; year++) {
            if (year % 2 == 0) {
                TOTAL += moneyBday;
                moneyBday += 10;
            } else {
                toys++;
            }
        }

        TOTAL += toys * priceT;
        TOTAL -= age / 2;


        if (TOTAL < priceW) {
            System.out.printf("No! %.2f",(priceW - TOTAL));
        } else {
            System.out.printf("Yes! %.2f",(TOTAL - priceW));
        }
    }
}