class Stone {
	int count;
	static int jewelry;

	Stone(int i) {
		this.count = i;
	}

	static void makeJewelry(Stone r, Stone g, Stone b) {
		r.count--;
		g.count--;
		b.count--;
		jewelry++;
	}

	static boolean checkJewelry(Stone r, Stone g, Stone b) {
		if (r.count >= 1 && g.count >= 1 && b.count >= 1) {
			return true;
		} else {
			return false;
		}
	}

	static void adjust(Stone r, Stone g, Stone b) {
		Stone x = r.count > g.count ? r : g;
		Stone max = x.count > b.count ? x : b;
		Stone n = r.count < g.count ? r : g;
		Stone min = n.count < b.count ? n : b;
		max.count -= 2;
		min.count += 1;
	}
}

public class No_91 {

	public static void main(String[] args) {
		java.util.Scanner sc = new java.util.Scanner(System.in);
		Stone red = new Stone(sc.nextInt());
		Stone green = new Stone(sc.nextInt());
		Stone blue = new Stone(sc.nextInt());

		while (red.count >= 0 && green.count >= 0 && blue.count >= 0) {
			if (Stone.checkJewelry(red, green, blue)) {
				Stone.makeJewelry(red, green, blue);
				;
			} else {
				Stone.adjust(red, green, blue);
			}
		}
		System.out.println(Stone.jewelry);

	}

}