#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<string>
#include<stack>
#include<queue>
#include<vector>
typedef long long int ll;
using namespace std;
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define REP(i,n) for (int i=0;i<(n);i++)
#define EREP(i,n) for (int i=1;i<=(n);i++)
const int MOD = 1000000007;
const int INF = 1000000;
     double N,M;
     double ans;
int main(){
    //ios::sync_with_stdio(false);
    cin>>M>>N;
    ans=M+(N/3);
    printf("%.10lf",ans);

}