#include <stdio.h>

typedef struct CELL *LIST;
struct CELL {
	int element;
	LIST next;
};

void insert(int x, LIST *pL)
{
	if ((*pL) == NULL) {
		(*pL) = (LIST) malloc(sizeof(struct CELL));
		(*pL)->element = x;
		(*pL)->next = NULL;
	}
	else if (x != (*pL)->element)
		insert(x, &((*pL)->next));
}