#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  int A,B;
  cin>>A>>B;
  if(A > 0 && B != 0){
      cout<<-1<<endl;
      return 0;
  }
  int N = 0;
  for(int i=1;i<=1e9;i++){
      N = A*N+B;
      if(!N){
          cout<<i<<endl;
          return 0;
      }
  }
  cout<<-1<<endl;
}