import java.util.*;

public class Exercise140{
  public static void main (String[] args){

    Scanner sc = new Scanner(System.in);

    int r = sc.nextInt();
    int g = sc.nextInt();
    int b = sc.nextInt();

    while(Math.abs(r - g) > 1 || Math.abs(r - b) > 1) {
      int biggest = Math.max(Math.max(r, g), b);
      int smallest = Math.min(Math.min(r, g), b);
      if(biggest == r){
        r -= 2;
      }else if(biggest == g){
        g -= 2;
      }else if(biggest == b){
        b -= 2;
      }

      if(smallest == r){
        r++;
      }else if(smallest == g){
        g++;
      }else if(smallest == b){
        b++;
      }
    }
    System.out.println(Math.min(Math.min(r, g), b));
  }
}