#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

inline bool check(ll n, ll k) {
  if (n == 1) return true;
  ll sum = 1;
  vector<ll> a(k - 1, 0);
  a.push_back(1);
  for (int i = k;; ++i) {
    a.push_back(sum);
    sum -= a[i - k];
    sum += a[i];
    if (sum > n) return false;
    if (sum == n) return true;
  }
  assert(false);
  return false;
}

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  ll n;
  cin >> n;
  for (int i = 2; i <= 100; ++i) {
    if (check(n, i)) {
      cout << i << '\n';
      return 0;
    }
  }
  cout << -1 << '\n';
  return 0;
}