#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;

long long fibonacci(int n){
    vector<long long> a(n + 1, 1);
    for(int i = 3; i <= n; ++i)a[i] = a[i - 1] + a[i - 2];
    return a[n];
}

int main(){
    int N;
    ll M;
    while(cin >> N >> M){
        ll fib = fibonacci(N);
        ll fusoku = fib - M;
        if(fusoku < 0){
            puts("-1");
        } else{
            int cnt = 0;
            for(int i = 3; i <= N && fusoku > 0; ++i){
                ll a = fibonacci(N + 1 - i);
                if(fusoku >= a){
                    cnt++;
                    fusoku -= a;
                }
            }
            if(fusoku == 0){
                cout << cnt << endl;
            } else{
                puts("-1");
            }
        }
    }
}