#include <iostream>
using namespace std;

#define STNUM 39

int main() {
  int cndy;

  while(cin>>cndy) {
    int c=cndy%STNUM;
    cout << "3C";
    if(c==0) cout << 39 << endl;
    else {
      if(c<10) cout<<"0";
      cout<<c<<endl;
    }
  }
  return 0;
}