import java.util.Scanner;

public class Yukicoder91 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long r = sc.nextLong(), g = sc.nextLong(), b = sc.nextLong();
		long sum = (r + g + b) / 3;
		long res = 0;
		while (true) {
			if (r == 0) {
				if (Math.max(b, g) > 2) {
					if (b > g) b -= 2;
					else g -= 2;
				}
				else break;
				r++;
			}
			if (g == 0) {
				if (Math.max(r, b) > 2) {
					if (r > b) r -= 2;
					else b -= 2;
				}
				else break;
				g++;
			}
			if (b == 0) {
				if (Math.max(r, g) > 2) {
					if (r > g) r -= 2;
					else g -= 2;
				}
				else break;
				b++;
			}
			r--;
			g--;
			b--;
			res++;
		}
		System.out.println("" + res);

	}
}