#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int x, y, z;
    cin >> x >> y >> z;
    if (x > y) swap(x, y);
    int tmp = min(y - x, z);
    z -= tmp;
    x += tmp;
    x += z / 2;
    y += z / 2;
    cout << min(x, y) << "\n";
    return 0;
}