// {{{ Templates
#include <bits/stdc++.h>

#define show(x) cerr << #x << " = " << x << endl

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
    os << "sz:" << v.size() << "\n[";
    for (const auto& p : v) {
        os << p << ",";
    }
    os << "]\n";
    return os;
}

template <typename S, typename T>
ostream& operator<<(ostream& os, const pair<S, T>& p)
{
    os << "(" << p.first << "," << p.second
       << ")";
    return os;
}


constexpr ll MOD = (ll)1e9 + 7LL;

template <typename T>
constexpr T INF = numeric_limits<T>::max() / 100;

// }}}

ll stone[3];
bool ok(ll n)
{
    ll shortage = 0;
    ll supply = 0;
    for (int i = 0; i < 3; i++) {
        if (stone[i] >= n) {
            supply += (stone[i] - n) / 2;
        } else {
            shortage += (n - stone[i]);
        }
    }
    return supply >= shortage;
}

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    cin >> stone[0] >> stone[1] >> stone[2];
    ll inf = 0;
    ll sup = 1e7 + 1;
    while (inf < sup) {
        const ll mid = (inf + sup) / 2;
        if (ok(mid)) {
            if (inf == mid) {
                break;
            }
            inf = mid;
        } else {
            sup = mid;
        }
    }
    cout << inf << endl;

    return 0;
}