import java.util.Scanner;
import java.lang.Math;

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();
    
    sc.close();

    while(whiteBall > 0){
      if(redBall > blueBall){
        blueBall++;
      }else if(redBall <= blueBall){
        redBall++;
      }
      whiteBall--;
    }
    System.out.println(Math.min(redBall,blueBall));
  }
}