import java.util.Scanner;
public class Main {
		public static void main(String[] args) {
			Scanner sc = new Scanner(System.in);
			long N = sc.nextInt();
			long D = sc.nextInt();
			long ans = 0;
			for(int i = 1; ; i++) {
				if((N * i) % D == 0) {
					ans = (N * i) / D - 1;
					break;
				}
			}
			System.out.println(ans);
			
		}
}