#include<stdio.h>
int main()
{
    int quantity);
    scanf("%d", &quality);
    if(quantity<0){
        printf("Invalid input");
        return 0;
    }
    float pricePerBook=100.0;
    float totalCost=quantity*pricePerBook;
    float discount=0.0;
    if(quantity>=1 && quantity<=5){
        discount=0.10;
    }else if(quantity>=6 && quantity<=10){
        discount=0.15;
    }else if(quantity>10){
        discount=0.20;
    }
    totalCost=totalCost-(totalCost*discount);
    printf("%.2f", totalCost);
    return 0;
}