1 //贪心，注意特判即可
 2 #include <iostream>
 3 using namespace std;
 4 int main()
 5 {
 6     int a,b,ans = 0;
 7     cin >> a >> b;
 8     while(a+b > 1 && (a != 1 || b != 1) && (a!=0 && b!=0))
 9     {
10         ++ans;
11         if(a > b) {a -= 2; b+=1;}
12         else {a+=1; b-=2;}
13     }
14     cout << ans << endl;
15     return 0;
16 }