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 in = new Scanner(System.in);
        while (in.hasNextLine()) { 
            String str = in.nextLine();
            String[] Arr = str.split(",");
		  //这里要用Long类型来存数据,如果给出的数太大Integer会报错
            Long number1 = Long.parseLong(Arr[1]);
            Long number2 = Long.parseLong(Arr[Arr.length-1]);
            System.out.println(number2-number1-1);
        }
    }
}