codeforces651----A. Joysticks

 //贪心，注意特判即可
 #include <iostream>
 using namespace std;
 int main()
 {
     int a,b,ans = ;
     cin >> a >> b;
     while(a+b >  && (a !=  || b != ) && (a!= && b!=))
     {
         ++ans;
         if(a > b) {a -= ; b+=;}
         else {a+=; b-=;}
     }
     cout << ans << endl;
     return ;
 }