#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_WARNINGS
#include "bits/stdc++.h"
#define rep(i,n) for(int i = 0;i < n;i++)
#define REP(i,n,k) for(int i = n;i < k;i++)
#define P(p) cout<<(p)<<endl;
#define pi 3.1415926535
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
int dx[] = { 0, 1, 0, -1 };
int dy[] = { -1, 0, 1, 0 };

unsigned long long sttoi(std::string str) {
	unsigned long long ret;
	std::stringstream ss; ss << str;
	ss >> ret;
	return ret;
}

ll gcd(ll a, ll b){
	if (b > a)swap(a, b);
	if (b == 0) return a;
	return gcd(b, a%b);
}
ll fibo[100];
ll calc(int n){
	if (fibo[n] != -1) return fibo[n];
	else return fibo[n] = calc(n - 1) + calc(n - 2);
}
void solve() {
	int n;
	ll m;
	fill(fibo, fibo + 100, -1);
	fibo[1] = 1;
	fibo[2] = 1;
	cin >> n >> m;
	ll g = calc(n)-m;
	int ans = 0;
	if (fibo[n] < m){
		P(-1);
		return;
	}
	for (int i = n-2; i > 0; i--){
		if (g == 0)break;
		if (fibo[i] <= g){
			ans++;
			g -= fibo[i];
		}
	}
	P(ans);
}

int main() {
	solve();
	return 0;
}