#include "bits/stdc++.h"
using namespace std;

int main(){
  int a,b,c;
  cin >> a >>b >> c;
  int  ans =0;
  while(a>0&&b>0){
      a--;
      b--;
      ans++;
  }
  c+=a;
  c+=b;
  ans+=c/2;
  cout << ans << endl;
}