#include<iostream>
#include<string>
using namespace std;
int main(){
  int s;
  string n[41]={"00","01","02","03","04","05","06","07","08","09","10","11","12","13","14","15","16","17","18","19","20","21","22","23","24","25","26","27","28","29","30","31","32","33","34","35","36","37","38","39"};
  while(cin>>s){
    while(s>39) s -= 39;
    cout << "3C" << n[s] << endl;
  }
  return 0;
}