#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <iomanip>
#include <cmath>
#include <map>
using namespace std;
using ll = long long;

int main()
{
  int x,y,z; cin >> x >> y >> z;
  int a = min(x, y);
  int b = max(x, y) - a;
  if(b > z) {
    cout << a + z << endl;
  } else {
    cout << a + b + (z - b) / 2 << endl;
  }
  return 0;
}