#include <iostream>
#include <cmath>
#include <set>

using lint = long long;

constexpr lint INF = 1LL << 30;

void solve() {
    lint a, b;
    std::cin >> a >> b;

    lint n = 0;
    std::set<lint> vis;
    for (int k = 0;; ++k) {
        n = a * n + b;

        if (vis.count(n) || std::abs(n) >= INF) break;
        if (n == 0) {
            std::cout << k + 1 << std::endl;
            return;
        }
        vis.insert(n);
    }

    std::cout << -1 << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}