#include <bits/stdc++.h>

#define VARNAME(x) #x
#define show(x) cerr << #x << " = " << x << endl

using namespace std;
using ll = long long;
using ld = long double;

template <typename T>
vector<T> Vec(int n, T v)
{
    return vector<T>(n, v);
}
template <class... Args>
auto Vec(int n, Args... args)
{
    auto val = Vec(args...);
    return vector<decltype(val)>(n, move(val));
}
template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
    os << "sz:" << v.size() << "\n[";
    for (const auto& p : v) {
        os << p << ",";
    }
    os << "]\n";
    return os;
}

template <typename S, typename T>
ostream& operator<<(ostream& os, const pair<S, T>& p)
{
    os << "(" << p.first << "," << p.second
       << ")";
    return os;
}


constexpr ll MOD = (ll)1e9 + 7LL;
constexpr ld PI = static_cast<ld>(3.1415926535898);
template <typename T>
constexpr T INF = numeric_limits<T>::max() / 10;

int rec(const ll x, const ll y, const int d)
{
    if (d >= 10) {
        return INF<int>;
    }
    if (x == y) {
        return d;
    } else {
        return min({rec(y, x, d + 1), rec(x + y, x - y, d + 1)});
    }
}

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll x, y;
    cin >> x >> y;
    const int ans = rec(x, y, 0);
    cout << (ans == INF<int> ? -1 : ans) << endl;

    return 0;
}