#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int,int>;
#define rep(i,n) for(int i=0;i<n;i++)

const ll mod = ll(1e9) + 7;
const int INF = 1<<29;

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