#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll fib[100];
bool use[100];
int main(){
	fib[0]=fib[1]=1;
	for(int i=2;i<80;i++)	fib[i]=fib[i-1]+fib[i-2];
	ll n,m;	cin>>n>>m;	m=fib[n-1]-m;
	int ans=0;
	for(int i=n-3;i>=0;i--){
		if(not(use[i]) and m>=fib[i]){
			m-=fib[i];
			ans++;
			use[i]=true;
		}
	}
	if(m==0)	cout<<ans<<endl;
	else 	cout<<-1<<endl;
	return 0;
}