// editor4
#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.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.total_coast=gross*(1.0f-order.disc.discountRate);
    printf("%.2f",order.total_cost);
    return 0;
}