package no415;

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		long d = sc.nextLong();
		System.out.println(n / gcd(n,d) - 1);
	}
	public static long gcd(long a,long b) {
		while(b!=0) {
			long r = a%b;
			a = b;
			b = r;
		}
		return a;
	}
}