#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
	int n;
	ll m;
	cin>>n>>m;
	ll fib[80];
	fib[0]=fib[1]=1;
	for(int i=2; i<n; i++) fib[i]=fib[i-1]+fib[i-2];
	ll d=fib[n-1]-m;
	int ans=0;
	for(int i=n-3; i>=0; i--){
		if(d>=fib[i]){
			d-=fib[i];
			ans++;
		}
	}
	if(d!=0) cout<<-1<<endl;
	else cout<<ans<<endl;
    return 0;
}