#include<stdio.h>
struct book
{
    int n;
};
int main()
{
    struct book a;
    scanf("%d",&discount.n);
    if(a.n<0)
    {
        printf("Invalid input");
    }
    else
    {
        float d=0.0
        float cost=a.n*100;
        if(a.n<=5)
        {
            d=0.10;
        }
        else if(a.n>=6&&a.n<=10)
        {
            d=0.15;
        }
        else if(a.n>10)
        {
            d=0.20;
        }
        float m=cost-(cost*d);
        printf("%.2f",m);
    }
}