#include<cstdio>
#define buf 1000
using namespace std;
void Answer(int ans);

int main(void){
	int ans,n;
	char str[buf];

	for( ;fgets(str,sizeof(str),stdin)!=NULL; ){
		sscanf(str,"%d",&n);
		ans=n%39;
		Answer(ans);
	}
	return 0;
}

void Answer(int ans){
	printf("3C");
	if(ans==0)
		printf("%d\n",ans+39);
	else if(ans<10)
		printf("0%d\n",ans);
	else 
		printf("%d\n",ans);
}