#include <stdio.h>
int main()
{
    int dian;
    double fee=0;

    scanf("%d",&dian);

    if(dian<=150)
    {
        fee=0.4463*dian;
    }

    else if(dian<=400)
    {
        fee=0.4463*150+(dian-150)*0.4663;
    }

    else 
    {
        fee=0.4463*150+0.4463*250+(dian-400)*0.5663;
    }

    printf("%.1lf",fee);
}