import java.util.*;
import java.math.*;
public class Main{
	public static void main(String... args){
		Scanner scan = new Scanner(System.in);
		int r = scan.nextInt();
		int g = scan.nextInt();
		int b = scan.nextInt();
		System.out.println(Calc(r,g,b));
	}

	public static int Calc(int r,int g,int b){
		int red=r,green=g,blue=b;
		int sum = 0;
		while(true){
			if(red == 0){
				if(Math.max(green,blue) > 2){
					if(blue > green){
						blue -= 2;
					}else{
						green -= 2;
					}
				}else{
					break;
				}
				red++;
			}
			if(green == 0){
				if(Math.max(red,blue) > 2){
					if(blue > red){
						blue -= 2;
					}else{
						red -= 2;
					}
				}else{
					break;
				}
				green++;
			}
			if(blue == 0){
				if(Math.max(red,green) > 2){
					if(green > red){
						green -= 2;
					}else{
						red -= 2;
					}
				}else{
					break;
				}
				blue++;
			}
			red--;green--;blue--;
			sum++;
		}
		return sum;

	}
}