import java.util.Scanner;

public class HelloWorld {
		public static void main (String[] args) {
			Scanner sc = new Scanner(System.in);
			int a = sc.nextInt();
			int b = sc.nextInt();
			sc.close();
			int temp = 0;

			if (a > 0 && b > 0) {
				System.out.println(-1);
			}else {
				for (int i = 0;i < 1000 ; i ++) {
					temp = a * temp + b;
					if (temp == 0) {
						System.out.println(i + 1);
						break;
					}
					if (i == 999) {System.out.println(-1);}
				}
			}


	}
}