#include<bits/stdc++.h>
using namespace std;
#define ALL(x) begin(x),end(x)
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 998244353
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;
 
template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==(int)v.size()?"":" ");
    return os;
}
template<typename T>
istream &operator>>(istream &is,vector<T>&v){
    for(T &x:v)is>>x;
    return is;
}

// Zeckendorf's Theoram

signed main(){

    const int k=10;
    vector<ll> f(k+1);
    f[1]=1,f[2]=1;
    for(int i=3;i<=k;i++) f[i]=f[i-1]+f[i-2];

    ll n,m;cin>>n>>m;
    ll dif=f[n]-m;
    if(dif<0){
        cout<<-1<<endl;
        return 0;
    }
    int res=0;
    for(int i=n-2;i>0;i--){
        if(f[i]<=dif){
            dif-=f[i],res++;
        }
    }
    if(dif){
        cout<<-1<<endl;
    }else{
        cout<<res<<endl;
    }

    return 0;
}