#include<bits/stdc++.h>

using namespace std;
using ll = long long int;
using lc = complex<double>;

int main(void) {
    constexpr ll MOD = 1e9 + 7;
    constexpr double PI = acos(-1);
    cout << fixed << setprecision(32);
    cin.tie(0); ios::sync_with_stdio(false);

    ll a, b;
    cin >> a >> b;

    ll n = 0, i = 0;
    do {
        n = a*n + b;
        i++;
    } while(-1e10 < n && n < 1e10 && n != 0 && i < 1e6);

    cout << (n == 0 ? i : -1) << endl;
}