#include<iostream>
#include<cstdio>
#include<cstring>
#include <cstdlib>  
#include <math.h>
#include <cmath>
#include<cctype>
#include<string>
#include<set>
#include<iomanip>
#include <map>
#include<algorithm>
#include <functional>
#include<vector>
#include<climits>
#include<stack>
#include<queue>
#include<bitset>
#include <deque>
#include <climits>
#include <typeinfo>
#include <utility> 
using namespace std;
using ll = long long;
using R = double;
using Data = pair < ll, vector <ll>>;
const ll MOD = 1e9 + 7;
const ll inf = 1LL << 60;
struct edge { ll from; ll to; ll cost; };
typedef tuple<ll, ll, ll>T;
typedef pair<ll, ll>pll;
#define all(x) (x).begin(),(x).end()
#define rep(i,m,n) for(ll i = m;i < n;++i)
#define pb push_back
#define fore(i,a) for(auto &i:a)
#define rrep(i,m,n) for(ll i = m;i >= n;--i)
#define INF INT_MAX/2

ll N, M;
ll fib[83];
int main(){
	cin >> N >> M;

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

	ll D = fib[N] - M;
	int ans = 0;
	if (D < 0) {
		cout << -1 << endl;
	}
	else {
		int cur = N;
		while (1) {
			if (fib[cur] <= D) {
				D -= fib[cur];
				ans++;
				cur--;
			}
			else {
				cur--;
			}
			if (D == 0)break;
		}
		cout << ans << endl;
	}


	return 0;
}