#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <string>
#include <vector>
#include <iostream>
#include <iomanip>
#include <stdlib.h>

using namespace std;

int main()
{
  int n,m;
  cin >> n >> m;

  cout << fixed << setprecision(10) << (double)n + (double)m/3 << endl;

  return 0;
}