#include <iostream>
#include <vector>
using namespace std;

int main() {
	int n;
	long long m;
	cin >> n >> m;

	vector<long long> dp(n);
	dp[0] = 1;
	dp[1] = 1;

	for (int i = 2; i < n; i++) {
		dp[i] = dp[i - 1] + dp[i - 2];
	}

	if (dp[n - 1] == m) {
		cout << 0 << endl;
	}
	else if (dp[n - 1] < m) {
		cout << -1 << endl;
	}
	else {
		long long diff = dp[n - 1] - m;
		int count = 0;
		for (int i = n - 3; i >= 0; i--) {
			if (diff >= dp[i]) {
				diff -= dp[i];
				count++;
				if (diff == 0) {
					cout << count << endl;
					break;
				}
			}
		}
	}
	
	return 0;
}