#include <stdio.h>

int main() {
    float price;
    int month, date, vote;
    scanf("%f %d %d %d", &price, &month, &date, &vote);
    if( month == 11 && date == 11 )
    {
        price *= 0.7;
        if(vote)
        {
            price -= 50;
            if(price>0)
            printf("%.2f",price);
            else
            printf("0.00");
        }
        else
        {
            printf("%.2f",price);
        }        
    }
    else if( month == 12 && date == 12 )
    {
        price *= 0.8;
        if(vote)
        {
            price -= 50;
            if(price>0)
            printf("%.2f",price);
            else
            printf("0.00");
        }
        else
        {
            printf("%.2f",price);
        }
    }
    else
    {
        printf("%.2f\n",price);
    }
    return 0;
}