/* -*- coding: utf-8 -*-
 *
 * 320.cc: No.320 眠れない夜に - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 80;

/* typedef */

typedef long long ll;

/* global variables */

ll fs[MAX_N + 1];

/* subroutines */

/* main */

int main() {
  int n;
  ll m;
  cin >> n >> m;

  fs[0] = 0, fs[1] = fs[2] = 1;
  for (int i = 3; i <= n; i++) fs[i] = fs[i - 1] + fs[i - 2];
  //printf("fs[%d]=%lld\n", n, fs[n]);

  int ans;

  if (fs[n] < m) ans = -1;
  else if (fs[n] == m) ans = 0;
  else {
    ans = 0;
    ll d = fs[n] - m;
    for (int k = n - 2; d > 0 && k > 0; k--)
      if (d >= fs[k]) {
	//printf("d=%lld, fs[%d]=%lld\n", d, k, fs[k]);
	ans++, d -= fs[k];
      }
  }

  printf("%d\n", ans);
  return 0;
}