#include <stdio.h>
#include <iostream>

using namespace std;

int main() {
	int t;

	while (cin >> t){
		while (t / 39 != 0) {
			t = t - 39;
		}

		if (t == 0) {
			t = 39;
		}

		printf("3C%02d\n",t);
	}
	return 0;
}