#include <stdio.h>int main(){float price = 0;int month, day, hasP = 0;scanf("%f %d %d %d", &price, &month, &day, &hasP);float cut = 0;if(month == 11 && day == 11){cut = 0.7;}else if(month == 12 && day == 12){cut = 0.8;}float pay = price*cut - 50*hasP;if(pay <= 0){printf("0.00");}else{printf("%.2f", pay);}}