import java.awt.Frame;
import java.net.NetworkInterface;
import java.util.*;

public class Main {
	static long gcd(long a,long b){
		return b == 0 ? a : gcd(b, a%b);
	}
	static long lcm(long a, long b){
		return a*b/gcd(a, b);
	}
	static int[] dx = {0,1,0,-1};//→↓←↑
	static int[] dy = {1,0,-1,0};
	static class Pair{
		long weight,value;
		public Pair(long weight,long value) {
			// TODO Auto-generated constructor stub
			this.weight = weight;
			this.value = value;
		}
	}
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int a = sc.nextInt();
		int b = sc.nextInt();
		if(a==b){
			System.out.println(0);
			return;
		}
		
		if(a<b){
			System.out.println(b-1-1);
		}else{
			System.out.println(2000000000-b-1);
		}
	}
}