#include <bits/stdc++.h>
using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)

int main() {
	int n;
	while (cin >> n) {
		string ans = "3C";
		int num = n % 39;
		if (num == 0) num = 39;
		ans.push_back(num / 10 + '0');
		ans.push_back(num % 10 + '0');
		cout << ans << endl;
	}
	return 0;
}