#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using pii = pair<int, int>;

int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(10);
  
  int a;
  while (cin >> a) {
    cout << "3C" << setfill('0') << setw(2) << (a % 39 == 0 ? 39 : a % 39) << endl;
  }

  return 0;
}
