#include <iostream>
using namespace std;
int main(void){
    int a; //キャンディーの個数

    while(cin >> a){

        if(a % 39 == 0)
            cout << "3C39" << endl;
        else{
            if(a % 39 < 10)
                cout << "3C0" << a % 39 << endl;
            else
                cout << "3C" << a % 39 << endl;
        }
    }
}
