
#include <iostream>
#include<string>
#include<cstdio>
#include<cmath>
#include<algorithm>
#include<vector>
using namespace std;
int main(){
    int a,b;
    while(cin>>a){
        b=a%39;
        if(b==0){
            printf("3C39");
            cout<<endl;
        }else{
            printf("3C%02d",b);
            cout<<endl;
        }
    }
    return 0;
}