#include<iostream>
#include<cstdio>
using namespace std;

int main(){

  int n;

  while(cin >> n){
    int m = 0;

    for(int i=0;i<n;i++){
      m++;
      if(m == 40) m = 1;
    }

    printf("3C%02d\n",m);

  }
}