#include <cstdio>

int main(){
	int n;
	int num;
	
	while(scanf("%d", &n) != EOF){
		num = n % 39;
		printf("3C");
		if(num < 10 && num != 0) putchar('0');
		if(num == 0) num = 39;
		printf("%d\n", num);
	}
	return 0;
}