#include<stdio.h>
int main(){
float discount;
scanf("%f",&discount);
if(discount<=1000){
printf("%f\n",discount);
return 0;
}
if(1000<discount && discount<2000){
printf("%f\n",0.95*discount);
return 0;
}
if(2000<=discount && discount<3000){
printf("%f\n",0.9*discount);
return 0;
}
if(discount > 5000 && discount < 8000){
printf("%f\n",discount * 0.8);
return 0;
}
}