/* Mon Oct 27 23:28:17 JST 2003 */
/* Tue Oct 28 00:25:32 JST 2003 */
#include <stdio.h>
#include <limits.h>

#define FLOOR 0
#define PILLAR 1
#define CARGO 2
#define GOAL 3
#define MAN 4

int w, h;
int map[9][9];
int already[9][9][4];
int gx, gy;
int min = INT_MAX;

void output(int cx, int cy, int mx, int my)
{
  int x, y;

  for (y = 0; y < h; y++) {
    for (x = 0; x < w; x++) {
      if (x == cx && y == cy) { printf("  ? ", CARGO); }
      else if (x == mx && y == my) { printf("  @ ", MAN); }
      else if (x == gx && y == gy) { printf("  X ", GOAL); }
      else printf("%3d ", map[y][x]);
    }
    printf("\n");
  }
  printf("-----\n");
}

int rec(int cx, int cy, int mx, int my, int move)
{
  int x, y, done, dist, i, j, result;
  int dx[4] = {0, 1, 0, -1};
  int dy[4] = {1, 0, -1, 0};
  int capable[4] = {0, 0, 0, 0};

#if 0
  output(cx, cy, mx, my);
#endif
  if (cx == gx && cy == gy) { return move; }

  map[my][mx] = (-1);
  for (dist = -1; ; dist--) {
    done = 0;
    for (y = 0; y < h; y++) {
      for (x = 0; x < w; x++) {
	if (map[y][x] == dist) {
	  for (i = 0; i < 4; i++) { 
	    if (map[y+dy[i]][x+dx[i]] == FLOOR &&
		!(y+dy[i] == cy && x+dx[i] == cx)) {
	      map[y+dy[i]][x+dx[i]] = dist-1;
	      done = 1;
	    }
	  }
	}
      }
    }
    if (!done) break;
  }
  for (i = 0; i < 4; i++) {
    if (map[cy+dy[i]][cx+dx[i]] < 0) { capable[i] = 1; }
  }
  for (y = 0; y < h; y++) {
    for (x = 0; x < w; x++) {
      if (map[y][x] < 0) { map[y][x] = 0; }
    }
  }

  for (i = 0; i < 4; i++) {
    if (capable[i] && already[cy][cx][i]) { return INT_MAX; }
  }

  for (i = 0; i < 4; i++) {
    if (!capable[i]) continue;

    if (map[cy-dy[i]][cx-dx[i]] == FLOOR) {
      already[cy][cx][i] = 1;
      result = rec(cx-dx[i], cy-dy[i], cx, cy, move+1);
      if (result < min) min = result;
      already[cy][cx][i] = 0;
    }
  }

  return INT_MAX;
}

int main()
{
  int x, y, i;
  int cx, cy;
  int mx, my;

  while (1) {
    scanf("%d %d", &w, &h);
    if (w == 0 && h == 0) break;

    w += 2; h += 2;
    for (y = 0; y < h; y++) {
      for (x = 0; x < w; x++) {
	if (x == 0 || y == 0 || x == w-1 || y == h-1) { map[y][x] = 1; continue; }
	scanf("%d", &map[y][x]);
	if (map[y][x] == CARGO) { cx = x; cy = y; map[y][x] = FLOOR; }
	if (map[y][x] == GOAL)  { gx = x; gy = y; map[y][x] = FLOOR; }
	if (map[y][x] == MAN)   { mx = x; my = y; map[y][x] = FLOOR; }
	for (i = 0; i < 4; i++) { already[y][x][i] = 0; }
      }
    }

    min = INT_MAX;
    rec(cx, cy, mx, my, 0);
    if (min == INT_MAX) printf("%d\n", -1);
    else printf("%d\n", min);
  }
}