import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int l = sc.nextInt();
		int r = sc.nextInt();
		int m = sc.nextInt();
		sc.close();

		System.out.println(Math.min(r - l + 1, m));
	}
}