#include<bits/stdc++.h>

using namespace std;
using ll = long long;


int main()
{
    ll a, b; cin >> a >> b;
    ll n = 0;
    for(int i = 0; i <= 1e6; i++) {
        n = a * n + b;
        if(abs(n) >= 1e9+10) {
            cout << -1 << endl;
            return 0;
        }
        if(!n) {
            cout << i + 1 << endl;
            return 0;
        }
    }
    cout << -1 << endl;
}