#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=int(a);i<=int(b);++i)
using namespace std;
template<class A>void pr(A a){cout << (a) << endl;}
template<class A,class B>void pr(A a,B b){cout << a << " "  ;pr(b);}
template<class A,class B,class C>void pr(A a,B b,C c){cout << a << " " ;pr(b,c);}
template<class A,class B,class C,class D>void pr(A a,B b,C c,D d){cout << a << " " ;pr(b,c,d);}
typedef long long ll;
typedef pair<ll, ll> l_l;
typedef pair<int, int> i_i;
int INF=numeric_limits<int>::max();
// for(int j=0;j<N;++j) {

int main(void) {
  ll MOD=pow(10,9)+7;
  ll a,b;cin>>a>>b;
  ll n = 0;
  int cnt=0;
  rep(i,-10000,10000) {
    cnt++;
    n=(n*a+b)%MOD;
    if(n==0) {
      pr(cnt);
      return 0;
    }
  }
  if(n!=0) {
    pr(-1);
  }
  return 0;
}