#include <iostream>
#include <algorithm>
using namespace std;

int main() {
    int R, G, B;
    cin >> R >> G >> B;

    int ans = 0;
    for (int i = 0; i < max({R, G, B}); i++) {
        int num = max(0, (R - i) / 2) + max(0, (G - i) / 2) + max(0, (B - i) / 2);
        num -= max(0, i - R) + max(0, i - G) + max(0, i - B);
        if (num >= 0) ans = i;
    }
    cout << ans << endl;
    return 0;
}