#include <iostream>
#include <cmath>
#include <string>
#include <vector>
#include <map>
#include <list>
#include <deque>
#include <algorithm>
#include <iomanip>

using namespace std;

int main() {
	int R, G, B;
	vector<int> ans;

	cin >> R >> G >> B;

	ans.push_back(R);
	ans.push_back(G);
	ans.push_back(B);

	while (true) {
		sort(ans.begin(), ans.end());

		if (ans[0] + 3 > ans[2]) break;
		ans[0]++;
		ans[2] -= 2;
	}

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