#include <bits/stdc++.h>

using namespace std;

int main() {
    vector<int> vt(3);
    for (int i = 0; i < 3; ++i) {
        cin >> vt[i];
    }

    sort(vt.begin(), vt.end());
    while (vt[2] >= vt[0] + 2) {
        vt[2] -= 2;
        vt[0]++;
        sort(vt.begin(), vt.end());
    }

    cout << vt[0] << endl;
    return 0;
}