#include<sgtdio.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;
}