#include<stdio.h>
int main(){
    int quantity;
    scanf("%d", &quantity);
    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;
}