#include <stdio.h>

int main() {
    int cost;
    scanf("%d", &cost);
    if(cost >= 100 && cost < 500)
        printf("%.1f", cost * 0.9);
    else if(cost >= 500 && cost < 2000)
        printf("%.1f", cost * 0.8);
    else if(cost >= 2000 && cost < 5000)
        printf("%.1f", cost * 0.7);
    else 
        printf("%.1f", cost * 0.6);
}