#include <iostream>
#include <string>
using namespace std;

#define MIN(a,b) ((a)<(b)?(a):(b))
#define MAX(a,b) ((a)>(b)?(a):(b))

int main()
{
	int M, N;
	cin >> M >> N;
	printf("%.12f\n", M + (double)1 / 3 * N);
	return 0;
}