#include <stdio.h>
#include <algorithm>
using namespace std;

long long a, b;

int main()
{
	scanf ("%d %d", &a, &b);
	long long n = b; int c = 1;
	while (n || c <= 2){
		n = a * n + b;
		c++;
	}
	if (n) c = -1;
	printf ("%d\n", c);
	return 0;
}