import java.util.*;

public class Main {
    static TreeSet<Integer> primes;
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int l = sc.nextInt();
		int r = sc.nextInt();
		int m = sc.nextInt();
		System.out.println(Math.min(m, r - l + 1));
	}
}