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

int main() {
  int X, Y, Z;
  cin >> X >> Y >> Z;
  if (X > Y) swap(X, Y);
  int z = Z;
  Z = Z - abs(X - Y);
  X = min(Y, X + z);
  cout << ((Z >= 0) ? min(X, Y) + Z / 2 : min(X, Y)) << "\n"; 
}