#include <stdio.h>
int main()
{
float a,s,c;
int b,m,d;
scanf("%f %d %d %d",&a,&b,&m,&d);
c=b==11?0.7:0.8;
s=d==1?a*c-50:a*c;
if(s<0)
    s=0.00;
printf("%.2f",s);
return 0;
}