#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <algorithm>
#include <numeric>
#include <functional>
#include <set>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
#include <climits>

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define FOE(i,a) for(auto i : a)
#define ALL(c) (c).begin(), (c).end()
#define EXIST(v, n) (std::find(v.begin(), v.end(), 1) != v.end())

using namespace std;

int main(int argc, char *argv[]) {
    int R, G, B, ans = 0;
    cin >> R >> G >> B;
    vector<int> s = { R, G, B };

    while (true) {
        sort(ALL(s));
        if (*min_element(ALL(s)) >= 1) { s[0] -= 1; s[1] -= 1; s[2] -= 1; ans++; }
        else if (s[2] >= 3)            { s[0]++; s[2] -= 2; }
        else { break; }
    }

    cout << ans << endl;
}