#include<stdio.h>
struct Bookinfo{
   int quantity;
   float price_per_book;
}b;
union DiscountData{
    float discount;
    float finalAmount;
}d;
int main(){
    b.price_per_book = 100;
    scanf("%d",&b.quantity);
    if(b.quantity < 0){
        printf("Invalid input");
        return 0;
    }
    float totalCost = b.quantity * b.price_per_book;
    if(b.quantity >= 1 && b.quantity <= 5){
    d.discount = 0.10;
    }
    else if(b.quantity >= 6 && b.quantity <= 10){
        d.discount = 0.15;
    }
    else if(b.quantity > 10){
        d.dicount = 0.20;
    }
    else{
        d.discount = 0.0;
    }
    d.finalAmount = totalCost - (totalCost * d.dicount);
    printf("%0.2f",d.finalAmount);
    return 0;
}