import java.util.Scanner;

public class No920 {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    
    int redBall = sc.nextInt();
    int blueBall = sc.nextInt();
    int whiteBall = sc.nextInt();
    int purpleBall = 0 ;
    
    if((redBall + blueBall) == 0){
      purpleBall = whiteBall / 2;
    }else{
        while(redBall > 0 && blueBall > 0){
          redBall--;
         blueBall--;
         purpleBall++;
        }
        while(whiteBall > 0){
            if((redBall + blueBall) > 0){
                if(redBall < blueBall){
                    whiteBall--;
                    blueBall--;
                    purpleBall++;
                }else if (redBall > blueBall){
                    whiteBall--;
                    redBall--;
                    purpleBall++;
                }else {
                    if(whiteBall < 2){
                        break;
                    }else{
                        whiteBall -= 2;
                        purpleBall++;
                    }
                }   
            }
        }
    }
    sc.close();
    System.out.println(purpleBall);
  }
}