#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

int f(long long x, long long y, int c) {
  if (c == 9) return 1000;
  if (x == y) return 0;
  return min(f(y, x, c + 1), f(x + y, x - y, c + 1)) + 1;
}

int main() {
  long long x, y;
  cin >> x >> y;

  int ans = f(x, y, 0);

  if (ans >= 1000) {
    cout << -1 << endl;
  } else {
    cout << ans << endl;
  }
}