#include <stdio.h>
int main () {
double a,b0,b1,c;
while(1){
scanf("%lf",&a);
if(a==-1){
break;
}
b1+=a;
b0=b1-a;
if(b1<=2760){
c+=a*0.538;
}
else if(b1>2760&&b0<=2760){
c+=(b1-2760)*0.588+(2760-b0)*0.538;
}
else if(b1<=4800){
c+=a*0.588;
}
else if(b1>4800&&b0<=4800){
c+=(b1-4800)*0.838+(4800-b0)*0.588;
}
else if(b1>4800){
c+=a*0.838;
}
}
printf("%.1lf",c);
return 0;
}