import java.util.Scanner;
public class Import {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {

           Scanner scan = new Scanner(System.in);

           double gosti = Integer.parseInt(scan.nextLine());
           double cena = Integer.parseInt(scan.nextLine());
           double budget = Integer.parseInt(scan.nextLine());
           double torta = budget-(budget*0.90);
           double suma = 0;
   if (gosti > 20){
   cena=cena-(cena*0.25);
     suma = gosti*cena+torta;
          if (suma > budget){System.out.printf("No party! %.2f leva needed.",(budget-suma)*(-1));}
          else {System.out.printf("It is party time! %.2f leva left.",budget-suma);}}

          else if (gosti > 15){
   cena=cena-(cena*0.20);
   suma = gosti*cena+torta;
          if (suma > budget){System.out.printf("No party! %.2f leva needed.",(budget-suma)*(-1));}
          else {System.out.printf("It is party time! %.2f leva left.",budget-suma);}
          }
           else if (gosti > 10){
   cena=cena-(cena*0.15);
       System.out.println(cena);
   suma = gosti*cena+torta;
          if (suma > budget){System.out.printf("No party! %.2f leva needed.",(budget-suma)*(-1));}
          else {System.out.printf("It is party time! %.2f leva left.",budget-suma);}
          }
           else {suma = gosti*cena+torta;
           if (suma > budget){System.out.printf("No party! %.2f leva needed.",(budget-suma)*(-1));}
          else {System.out.printf("It is party time! %.2f leva left.",budget-suma);}}
   }}