#include <bits/stdc++.h>

using namespace std;

int main() {
  int x, y, z;
  cin >> x >> y >> z;
  if (x < y) {
    int diff = y - x;
    x += min(diff, z);
    z -= min(diff, z);
  } else if (x > y) {
    int diff = x - y;
    y += min(diff, z);
    z -= min(diff, z);
  }

  int add = z / 2;
  x += add;
  y += add;
  cout << min(x, y) << '\n';
}