#include <stdio.h>
#include <stdint.h>
#include <cmath>

int ri() {
	int n;
	scanf("%d", &n);
	return n;
}

int main() {
	int a = ri();
	int b = ri();
	int64_t cur = 0;
	int cnt = 0;
	for (; std::abs(cur) <= 4000000000; ) {
		cur = cur * a + b;
		cnt++;
		if (cnt >= 1000000) break;
		if (!cur) break;
	}
	printf("%d\n", cur ? -1 : cnt);
	return 0;
}