import java.math.*;
import java.util.*;
 
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int r = sc.nextInt();
        int g = sc.nextInt();
        int b = sc.nextInt();
        int min = Math.min(r, Math.min(g,b));
        int max = Math.max(r, Math.max(g,b));
        while(min<=max){
        	int temp=(min+max)/2;
        	int count=0;
        	if(temp>r){
        		count-=(temp-r);
        	}else{
        		count+=(r-temp)/2;
        	}
        	if(temp>g){
        		count-=(temp-g);
        	}else{
        		count+=(g-temp)/2;
        	}
        	if(temp>b){
        		count-=(temp-b);
        	}else{
        		count+=(b-temp)/2;
        	}
        	if(count>=0){
        		min=temp+1;
        	}else{
        		max=temp-1;
        	}
        }
        System.out.println(Math.min(min,max));
    }
}