#include<stdio.h>
struct order
{
    int quantity;
    float price_per_book;
    union {
        float 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.quantity>1 && order.quantity<=5){
        order.disc.discountRate=0.10f;
    }
    else if (order.quantity>=6 && order.quantity<=10)
    {
        order.disc.discountRate=0.15;
    }
    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.totel_cost=gross(order.disc.discountRate);
    printf("%2f",order.total_cost);
    return 0;
}