import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeSet;

public class Main {
	
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		final int R = sc.nextInt();
		final int G = sc.nextInt();
		final int B = sc.nextInt();
		
		final int min_RGB = Math.min(R, Math.min(G, B));
		
		int answer = min_RGB;
		int[] curs = {R - min_RGB, G - min_RGB, B - min_RGB};
		
		while(true){
			int max_pos = -1, min_pos = -1;
			int max = Integer.MIN_VALUE, min = Integer.MAX_VALUE;
			
			for(int i = 0; i < curs.length; i++){
				if(max < curs[i]){
					max = curs[i];
					max_pos = i;
				}
				if(min > curs[i]){
					min = curs[i];
					min_pos = i;
				}
			}
			
			//System.out.println(Arrays.toString(curs));
			if(curs[max_pos] < 2){ break; }
			
			curs[min_pos] += 1;
			curs[max_pos] -= 2;
			
			boolean flg = true;
			for(int i = 0; i < curs.length; i++){
				if(curs[i] < 1){
					flg = false;
					break;
				}
			}
			
			if(!flg){
				continue;
			}
			
			for(int i = 0; i < curs.length; i++){
				curs[i]--;
			}
			answer++;
		}
		
		System.out.println(answer);
	}
	
}