import java.util.*;
class A{
	static Scanner s = new Scanner(System.in);
	public static void main(String[] args){
		int p = s.nextInt(), j = s.nextInt();
		System.out.println(p/gcd(p,j)-1);
	}
	public static long gcd(long a, long b) {
		long m;
		while(a!=0) {
			m = Math.min(a, b);
			a = Math.max(a, b)%m;
			b = m;
		}
		return b;
	}
}