using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

class Magatro {
    static void Main() {
        string[] q = Console.ReadLine().Split(' ');
        int n = int.Parse(q[0]);
        int d = int.Parse(q[1]);
       long ans = (LCM(n, d) / d) - 1;
        Console.WriteLine(ans);
    }
    static long LCM(int x,int y) {
        long a = Math.Max(x, y);
        long b = Math.Min(x, y);
        long q = a * b;
        long r = a % b;
        while (r != 0) {
            a = b;
            b = r;
            r = a % b;
        }
        return q / b;
    }
}