#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main(void){
  ll a,b; cin >> a >> b;
  ll res = b;
  ll cnt = 1;
  ll ma = res;
  while(1){
      if(res == 0){
          cout << cnt << endl;
          return 0;
      }
      //おーばふろーしたか
      if(res < ma){
          cout << -1 << endl;
          return 0;
      }
      res = a*res + b;
      ma = max(res,ma);
      cnt++;
      if(cnt >= 1e5){
          cout << -1 << endl;
          return 0;
      }
  }
}