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

#define RREP(i,s,e) for (int i = e-1; i >= s; i--)
#define rrep(i,n) RREP(i,0,n)
#define REP(i,s,e) for (int i = s; i < e; i++)
#define rep(i,n) REP(i,0,n)

int main() {
    int rgb[3], ans;
    rep (i,3) cin >> rgb[i];
    ans = *min_element(rgb,rgb+3);
    rep (i,3) rgb[i] -= ans;
    sort(rgb,rgb+3);
    while (rgb[2] >= 3) {
        rgb[2] -= 2;
        rgb[0]++;
        sort(rgb,rgb+3);
        if (rgb[0] > 0) {
            ans++;
            rep (i,3) rgb[i]--;
        }
    }
    cout << ans << endl;
    return 0;
}