#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0, i##_len = (n); i < i##_len; i++)
#define reps(i, s, n) for(ll i = (s), i##_len = (n); i < i##_len; i++)
#define rrep(i, n) for(ll i = (n) - 1; i >= 0; i--)
#define rreps(i, e, n) for(ll i = (n) - 1; i >= (e); i--)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((ll)(x).size())
#define len(x) ((ll)(x).length())

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // ifstream in("input.txt");
    // cin.rdbuf(in.rdbuf());
    vector<ll> s(3);
    rep(i, 3) cin >> s[i];
    sort(all(s), greater<ll>());
    ll l = 0, h = 1e7 + 1;
    while((l + 1) < h) {
        ll m = (l + h) / 2;
        ll rem = 0;
        bool f = true;
        rep(i, 3) {
            if ((s[i] + rem) < m) {
                f = false;
                break;
            }
            if (s[i] >= m) {
                rem += (s[i] - m) / 2;
            }
            else {
                rem -= (m - s[i]);
            }
        }
        if (f) l = m;
        else h = m;
    }
    cout << l << endl;
    return 0;
}