import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
		
        Scanner sc = new Scanner(System.in);
		
       	int a = sc.nextInt();
		
        int b = sc.nextInt();
		
		int c=0;
		
		if(a<b){
			if(a==1 && b==2)	c=0;
			else if(a+1==b)	c=a-1;
			else	c=(b-a-1)+(a-1);
		}else if(a>b){
			if(a==2000000000)	c=a-b-1;
			else if(a-1==b)	c=2000000000-a;
			else c=(2000000000-a)+(a-b-1);
		}
        System.out.println(c);
    }
}