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

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

	long long low = 0;
	long long high = 1e12;

	while (high - low > 1) {
		long long mid = (low + high) / 2;

		long long overR = max(0ll, r - mid);
		long long overG = max(0ll, g - mid);
		long long overB = max(0ll, b - mid);

		long long lessR = max(0ll, mid - r);
		long long lessG = max(0ll, mid - g);
		long long lessB = max(0ll, mid - b);

		if (overR / 2 + overG / 2 + overB / 2 >= lessR + lessG + lessB) {
			low = mid;
		} else {
			high = mid;
		}
	}

	cout << low << endl;

	return 0;
}