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

int main() {
    int r, g, b;
    cin >> r >> g >> b;

    int high = max(max(r, g), b);
    int low = min(min(r, g), b);

    int middle;
    while (high > low) {
        middle = (high + low + 1) / 2;
        int rest = 0;
        rest += (r - middle >= 0) ? (r - middle) / 2 : r - middle;
        rest += (g - middle >= 0) ? (g - middle) / 2 : g - middle;
        rest += (b - middle >= 0) ? (b - middle) / 2 : b - middle;
        if(rest >= 0) low = middle;
        else high = middle - 1;
    }

    cout << high << endl;
}