//#define _GNU_SOURCE

#include <regex.h>
#include <search.h>
#include <stdio.h>
#include <stdlib.h>


#define arrlen(x) (sizeof(x)/sizeof((x)[0]))


struct point {
	int x;
	int y;
	int z;
};


int
point_cmp(struct point const * a, struct point const * b)
{
	if (a->x != b->x)
		return a->x - b->x;
	if (a->y != b->y)
		return a->y - b->y;
	return a->z - b->z;
}


int
point_cmp_t(void const * a, void const * b)
{
	return point_cmp(a, b);
}


// Get one of the faces of a cube
//
// x = left-right
// y = up-down
// z = front-back
//
// To uniquely identify the faces of a cube, we scale the cube by a factor of
// two, and then identify each face by the point at the face's center.
struct point *
cube_face(int x, int y, int z, int face)
{
	struct point * f;

	x *= 2;
	y *= 2;
	z *= 2;

	switch (face) {
	case 0: // Bottom face
		x += 1;
		z += 1;
		break;

	case 1: // Top face
		x += 1;
		y += 2;
		z += 1;
		break;

	case 2: // Left face
		y += 1;
		z += 1;
		break;

	case 3: // Right face
		x += 2;
		y += 1;
		z += 1;
		break;

	case 4: // Front face
		x += 1;
		y += 1;
		break;

	case 5: // Back face
		x += 1;
		y += 1;
		z += 2;
		break;

	default:
		return NULL;
	}

	if ((f = malloc(sizeof(struct point))) == NULL)
		return NULL;

	f->x = x;
	f->y = y;
	f->z = z;
	return f;
}


int
main()
{
	char buf[BUFSIZ];
	regex_t cube;
	regmatch_t coords[4];
	void * faces = NULL;
	int nfaces = 0;

	if (regcomp(&cube, "(-?[[:digit:]]+),(-?[[:digit:]]+),(-?[[:digit:]]+)", REG_EXTENDED) != 0) {
		fprintf(stderr, "Bad regex\n");
		return -1;
	}

	while (fgets(buf, sizeof(buf), stdin)
			&& regexec(&cube, buf, arrlen(coords), coords, 0) == 0)
	{
		int x, y, z, f;

		x = atoi(buf + coords[1].rm_so);
		y = atoi(buf + coords[2].rm_so);
		z = atoi(buf + coords[3].rm_so);

		for (f = 0; f < 6; ++f) {
			struct point * face = cube_face(x, y, z, f);

			struct point * exists = *((struct point **) tsearch(face, &faces, point_cmp_t));

			if (exists == face) {
				// Inserted new face
				++nfaces;
			}
			else {
				// Face already existed, so delete it
				tdelete(face, &faces, point_cmp_t);
				--nfaces;
				free(face);
				free(exists);
			}
		}
	}

	printf("Faces: %d\n", nfaces);

#ifdef _GNU_SOURCE
	tdestroy(faces, free);
#endif
	regfree(&cube);

	return 0;
}