// editor4
#include<stdio.h>
int main()
{
    int quantity;
    scanf("%d",&quantity);
    if(quantity<0)
    {
        printf("Invalid input");
        return 0;
    }
    float price_per_book=100.0f;
    float discount_rate=0.0f;
    if(quantity>=1&&quantity<=5)
    {
        discount_rate=0.10f;
    }
    else
    if(quantity>10)
    {
        discount_rate=0.20f;
    }
    float total=quantity*price_per_book;
    float final_amount=total*(1.0f-discount_rate);
    printf("%.2f",final;_amount);
    return 0;
}