#include <bits/stdc++.h>

using namespace std;

long long fib[80+1];

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  fib[0] = 0;
  fib[1] = 1;
  for (int i = 2; i <= 80; i++)
    fib[i] = fib[i-1] + fib[i-2];

  int n;
  long long m;
  cin >> n >> m;

  if (m > fib[n])
    cout << -1 << endl;
  else if (m == fib[n])
    cout << 0 << endl;
  else {
    long long x = fib[n] - m;
    int ret = 0;
    for (int i = n-2; i > 0; i--) {
      if (x >= fib[i]) {
        ++ret;
        x -= fib[i];
      }
    }
    if (x == 0)
      cout << ret << endl;
    else
      cout << -1 << endl;
  }

  return 0;
}