#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <string>
#include <numeric>
#include <cstring>
#include <cmath>
#include <set>
#include <queue>
#include <stack>

const int MOD = 1e9 + 7;
const int iINF = 100000000;
#define rep(i,n) for(int i=0;i<(n);i++)

using namespace std;
using ll = long long int;
using P = pair<int, int>;
using edge = struct{int to; int cost;};

int main()
{
    double ans;
    double M, N;
    cin >> M >> N;

    ans = M + N / 3;
    
    printf("%lf\n", ans);
    return 0;
}