import java.util.*;

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

  public static long gcd(long a, long b) {
    if(b == 0) return a;
    long M = Math.max(a, b);
    long m = Math.min(a, b);
    return gcd(m, M % m);
  }
}