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

int main() {
	int n;
	long long m;
	cin >> n >> m;
	vector<long long> fib(n);
	
	fib[0] = 1;
	fib[1] = 1;
	for(int i = 2; i < n; i++){
		fib[i] = fib[i-1] + fib[i-2];
	}
	
	m = fib[n-1] - m;
	int ans = 0;
	
	for(int i = n-3; i >= 0; i--){
		if(m >= fib[i]){
			ans++;
			m -= fib[i];
		}
	}
	
	if(m != 0){
		cout << -1 << endl;
	}else{
		cout << ans << endl;
	}
	
	return 0;
}