#include<stdio.h>
int main()
{
    int units;
    double bill = 0.0;
    scanf("%d", &units);
    if (units < 0) {
        printf("Invalid input\n");
        return 0;
    }
    
    if (units <= 100){
        bill = (100 * 0.10) + (unoits - 100)* 0.15;
    }
    else {
        bill = (100 * 0.10) + (100 * 0.15) + (units - 200) * 0.20;
    }
    printf("%.2f\n", bill);
    return 0;
}