#include <iostream>
#include <algorithm>
#include <cassert>
#include <cctype>
#include <complex>
#include <cstdio>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
using namespace std;

int n;

int main(){
	while(cin>>n){
		cout<<"3C";
		if(n%39==0)cout<<39<<endl;
		else{
			if(n%39<10)cout<<0;
			cout<<n%39<<endl;
		}
	}
}