#include <iostream>
using namespace std;

long long FIB[81];

int main()
{
	FIB[1] = 1; FIB[2] = 1;
	for (int i = 3; i < 81; i++)FIB[i] = FIB[i - 1] + FIB[i - 2];

	long long n, m; cin >> n >> m;
	long long yukichan = FIB[n] - m;
	int cnt = 0;
	if (yukichan == 0)cnt=0;
	else if (yukichan < 0)cnt = -1;
	else {
		int last = 81;
		while (yukichan) {
			for (int i = 1; i < last; i++) {
				if (FIB[i] > yukichan) {
					yukichan -= FIB[i - 1];
					cnt++;
					last = i - 1;
					break;
				}
				if (i == last - 1) {
					yukichan -= FIB[i];
					cnt++;
					last = i;
				}
			}
		}
	}

	cout << cnt << endl;

    return 0;
}