#include<stdio.h>
int main(){
	int c,d;
	double p,max;
	scanf("%d %d",&c,&d);
	if(3*d-c<0){
		max=4000.0*d;
	}else{
		if(5*c-2*d>0){
			max=4000.0*c/3.0+34000.0*(3*d-c)/39.0;
		}else{
			max=7000.0*c;
		}
		if(2*d-5*c>0){
			p=4000.0*d-6000.0*(3*d-c)/13.0;
		}else{
			p=2800.0*d;
		}
		max=(max<p)?p:max;
	}
	printf("%f\n",max);
	return 0;
}