#include<iostream>
#include<cstdio>
#include<algorithm>
#include<string>
#include<cstring>
using namespace std;
int main(){
	int n;
	while(scanf("%d",&n) != EOF){
        int ans = 0;
        if(n % 39 == 0) ans = 39;
        else ans = n % 39;
        printf("3C%02d\n",ans);
	}
	return 0;
}