#include <iostream>
#include <cassert>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  long long A, B; cin >> A >> B;
  long long N = B;
  long long P = 0;
  for (int i = 1; i < 1e7; i++) {
    N = A * N + B;
    if (abs(N) > abs(P)) {
      cout << -1 << endl;
      return 0;
    }
    if (N == 0) {
      cout << i << endl;
      return 0;
    }
    P = N;
  }
  cout << -1 << endl;
  return 0;
}