//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(int i=0; i<n; ++i)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
using namespace std;
using ll = int64_t;
using ld = long double;
using P = pair<int, int>;
using vs = vector<string>;
using vi = vector<int>;
using vvi = vector<vi>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQG = priority_queue<T, vector<T>, greater<T> >;
const int INF = 0xccccccc;
const ll LINF = 922337203685477580LL;
template<typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true);}
template<typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true);}
template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) { return is >> p.first >> p.second;}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) { return os << p.first << ' ' << p.second;}

const int N = 100;

//head

int n;
ll fib[N];
ll m;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  fib[0] = 0; fib[1] = 1;
  rep(i, 79) fib[i+2] = fib[i+1] + fib[i];
  cin >> n >> m;
  m = fib[n] - m;

  int cnt = 0;
  bool str = true;
  bool able = true;
  for(int i = n-2; i > 0; i--) {
    if(!able) {
      able = true;
      continue;
    }
    if(m >= fib[i]) {
      m -= fib[i];
      cnt++;
      if(!str) able = false;
    }
    else str = false;
  }

  cout << (m?-1:cnt) << endl;
}