#include <iostream>
#include <iomanip>

int main()
{
	int a;
	while (std::cin >> a) {
		if (a%39 != 0) std::cout << "3C" << std::setw(2) << std::setfill('0') << a%39 << std::endl;
		else std::cout << "3C39" << std::endl;
	}
	return 0;
}

