#include<bits/stdc++.h>
using namespace std;
int main(){
	int x,y;
	cin>>x>>y;
	double sum=0;
	if(x<=2) sum=6;
	else if(x>2&&x<=10) 
		sum=6+(x-2)*1.8;
	else if(x>10)
		sum=6+1.8*8+(x-10)*1.8*1.5;
	sum+=y/3; 
	if(sum==int(sum)) cout<<sum;
	else printf("%.1lf",sum);
	
	return 0;
}