import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();
		int y = sc.nextInt();
		int z = sc.nextInt();
		int max = 0;
		for (int i = 0; i <= z; i++) {
		    max = Math.max(max, Math.min(x + i, y + z - i));
		}
		System.out.println(max);
	}
}