#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <cmath>
#include <cstdlib>
#include <cstdio>
using namespace std;

int main(void){
	double a,b;
	cin>>a>>b;
	printf("%.9lf",a+1.0/3.0*b);
	return 0;
}