#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <cstring>
#include <map>
#include <queue>
#include <cmath>

#define MOD 1000000007
#define ll long long
#define ld long double

using namespace std;


int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  ld M,N;
  cin >> M >> N;

  cout << fixed << setprecision(9) << M+(N/3) << endl;
  return 0;
}