#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

int main(){
  ll A, B; cin >> A >> B;
  ll N = 0;
  for(ll i = 1; i <= 1e8; i++){
    N = A*N + B;
    if(N == 0){
      cout << i << endl;
      return 0;
    }
  }
  cout << -1 << endl;
}