package No400番台;

import java.util.Scanner;

public class Q415 {
	public static void main(String[] args) {
		new Q415().solver();
	}
	void solver() {
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong();
		long D = sc.nextLong();
		System.out.println(N / gcd(D, N) -1);
	}

	static long gcd(long t1, long t2) {
		if (t1 < t2) {
			long d = t2;
			t2 = t1;
			t1 = d;
		}
		if (t2 == 0)
			return t1;
		return gcd(t2, t1 % t2);
	}

}