#include <bits/stdc++.h>

//const static double	de_PI	= 3.14159265358979323846;
//const static int	de_MOD	= 1000000007;
//const static int	de_MAX	= 999999999;
//const static int	de_MIN = -999999999;

int main(void) {

	//std::ifstream in("123.txt");	std::cin.rdbuf(in.rdbuf());

	std::vector<int> A(3);
	std::cin >> A[0] >> A[1] >> A[2];

	int ans = 0;

	while (1) {
		std::sort(A.begin(), A.end());
		ans += A[0];
		for (int i = 2; i >= 0; i--) { A[i] -= A[0]; }
		if (A[2] <= 2) { break; }
		while (A[2] > 2 && A[2] >= A[1] && A[2] > A[0] && A[1] >= A[0]) {
			A[2] -= 2;
			A[0]++;
		}
	}

	std::cout << ans << std::endl;

}