#include <bits/stdc++.h>
using namespace std;
int main(void){
    int n;
    while (cin>>n) {
        if (n<=39) {
            if (n/10==0) {
                cout<<"3C"<<0<<n<<endl;
            } else {
                cout<<"3C"<<n<<endl;
            }
        } else {
            while(n>39){
                n=n-39;
            }
            if (n/10==0) {
                cout<<"3C"<<0<<n<<endl;
            } else {
                cout<<"3C"<<n<<endl;
            }
        }
    }
}

