#include"bits/stdc++.h"
using namespace std;
#define REP(k,m,n) for(int (k)=(m);(k)<(n);(k)++)
#define rep(i,n) REP((i),0,(n))
using ll = long long;

int main()
{
    int X, Y, Z;
    cin >> X >> Y >> Z;
    int res = min(X, Y);
    int left = abs(X - Y);
    if (left < Z) {
        res += (left + Z) / 2;
    }
    else {
        res += Z;
    }
    cout << res << endl;
    return 0;
}