import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String str = scanner.nextLine();
        String[] s =str.split(",");
        long n = Long.parseLong(s[3]);
        long m = Long.parseLong(s[1]);

            System.out.println(n-m-1);


    }
}