#include<stdio.h>
struct Order {
    int quantity;
    float price_per_book;
    union {
        float discountRate;
        int disocuntPercent;
    } 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.quantity>=1 && order.quantity<=5)
        {
            order.disc.discountRate = 0.10f;
            
        }
        else if(order.quantity>=6 && order.quantity<=10)
        {
            order.disc.discountRate=0.14;
        }
        else if(order,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;
        }