#include "bits/stdc++.h"
#include<unordered_map>
#include<unordered_set>
#pragma warning(disable:4996)
using namespace std;
using ld = long double;
template<class T>
using Table = vector<vector<T>>;
const ld eps=1e-9;

//// < "D:\D_Download\Visual Studio 2015\Projects\programing_contest_c++\Debug\a.txt" > "D:\D_Download\Visual Studio 2015\Projects\programing_contest_c++\Debug\b.answer"
string to_string_keta(const long long int l, const int keta) {
	ostringstream oss;

	oss << std::setw(keta) << std::setfill('0') << l;

	return oss.str();
}

int main() {
	int a; 
	while (cin >> a) {
		a %= 39;
		if (!a)a = 39;
		cout << "3C" << to_string_keta(a,2) << endl;
	}
	return 0;
}