#include <bits/stdc++.h>
using namespace std;
void zanj0() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}
string win = "sjfnb";
string lose = "cslnb";
void solve() {
  long long int n;
  cin >> n;
  map<long long int, long long int> freq;
  long long int sum = 0;
  vector<long long int> v(n);
  for (long long int i = 0, x; i < n; i++) {
    cin >> x;
    v[i] = x;
    freq[x]++;
    sum ^= x & 1;
    sum ^= (i & 1);
  }
  bool ok = true;
  long long int bad = 0;
  for (auto& it : freq) {
    if (it.second > 2) ok = false;
    if (it.second == 2) bad++;
  }
  if (ok) {
    for (long long int i : v) {
      if (i && !freq.count(i - 1)) {
        if (bad == (freq[i] == 2)) {
          bad = -1;
        }
      }
    }
    if (bad != -1) ok = false;
  }
  ok = ok && sum == 1;
  cout << (ok ? win : lose) << "\n";
}
int main() {
  zanj0();
  solve();
  return 0;
}
