// editor   
#include<stdio.h>
 struct Order {
     int quantity;
     float price_per_book;
     union{
         float discountRate;
         int discountPercent;
     }disc;
     float total_cost;
 };
 int main() {
     struct Order order;
     order.price_per_book = 100.0f;
     scanf("%d",&order.quantity);
     if(order.quantity<0) {
         printf("Invalid input");
         return 0;
     }
 }
 if(order.quqntity>=1 && order.quantity<=5){
     order.disc.discountRate = 0.10f
 }
 else if(order.quantity>=6 && order.quantity<=10)
 {
     order.disc,discountRate=0.20f;
 }
 else if(orde.quantity>10){
     order.disc,discountRate =0.20f;
 }
 else{
     order.disc.discountRate =0.0f;
     
 }
 float gross = order.quantity * order.price_per_book;
 order.total_cost=gross*(1.0f - order.disc.discountRate);
 printf("%.2f",order.total_cost);
 
    return 0;
    
}