#include<bits/stdc++.h> using namespace std; using ll = long long; using ld = long double; #define rep(i,n) for(int i=0;i<(int)(n);i++) #define reps(i,s,n) for(int i=(int)(s);i<(int)(n);i++) #define allsort(v) sort(v.begin(),v.end()) #define allsortg(v)sort(v.begin(),v.end(),greater<int>()); const ll mod = 1e9 + 7; const int INF = 1e9; int main() { cin.sync_with_stdio(false); ld M, N; cin >> M >> N; cout << setprecision(15)<<M + N / 3 << endl; return 0; }