#include<stdio.h>
int main(){
int month=0,day=0,coupon=0;
float price=0,total=0;
scanf("%f %d %d %d",&price,&month,&day,&coupon);
if(month==11&&day==11){
price=price*0.7;
if(coupon==1){
price=price-50;
}
}
else if(month==12&&day==12){
price=price*0.8;
if(coupon==1){
price=price-50;
}
}
else{
if(coupon==1){
price=price-50;
}
}
if(price<=0){//防止商家倒给钱
price=0;
}
printf("%.2f",price);
return 0;
}