#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <string>
#define REP(i, n) for(int i = 0;i < n;i++)
#define ll long long
#define INF 114514
using namespace std;




int main(){
	int m;
	m = 39;
	int candy;
	while (cin >> candy) {
		cout <<"3C"<< candy%m << endl;
	}
	return 0;
}