#include<iostream>
#include<cstdio>
using namespace std;
int main(){
  int bell,number;
  while(scanf("%d",&bell)!=EOF){
    number=0;
    while(bell!=0){
      if(bell>39){
	bell-=39;
      }
      else{
	bell--;
	number++;
      }
    }
    if(number<10){
      cout << "3C0" << number << endl;
    }
    else{
      cout << "3C" << number << endl;
    }
  }
}