#include <bits/stdc++.h>

using namespace std;

unsigned long long int f[81];


int main(void)
{
	cin.tie(0);
	ios::sync_with_stdio(false);

	f[1] = 1;
	f[2] = 1;
	for (int i = 3; i <= 80; i++)
	{
		f[i] = f[i - 1] + f[i - 2];
	}

	int n;
	unsigned long long int m;

	cin >> n >> m;
	long long int diff = f[n];
	diff -= m;

	if (diff < 0)
	{
		cout << -1 << '\n';
		return 0;
	}
	int res = 0;

	for (int i = 80; i >= 1; i--)
	{
		if (diff >= f[i])
		{
			diff -= f[i];
			res++;
		}
	}

	if (diff > 0) res = -1;

	cout << res << '\n';

	return 0;
}