#include <bits/stdc++.h>
using namespace std;

int main() {
  long long int a, b, n = 0, ans = 0;

  cin >> a >> b;
  if (a > 0 && b > 0) {
    cout << "-1"
         << "\n";
    return 0;
  }
  do {
    int x = n;
    n = a * n + b;
    ans++;
  } while (n != 0);
  cout << ans << "\n";
}