#include <iostream>
#include <set>
#include <complex>
#include <climits>

using namespace std;

typedef complex<int> POS;

const POS DIR[] = {
  POS(1, 0),
  POS(-1, 0),
  POS(0, 1),
  POS(0, -1)
};

int TABLE[20][20];
POS GOAL;

struct STATE{
  POS man;
  POS cargo;
  int push;

  bool operator<(const STATE& rh)const{
    if (push == rh.push){
      if (man.real() == rh.man.real()){
	if (man.imag() == rh.man.imag()){
	  if (cargo.real() == rh.cargo.real()){
	    return cargo.imag() < rh.cargo.imag();
	  }
	  return cargo.real() < rh.cargo.real();
	}
	return man.imag() < rh.man.imag();
      }
      return man.real() < rh.man.real();
    }
    return push < rh.push;
  }

  STATE() : push(0){}
  STATE(int state) : push(0){
    cargo = POS(state & 0xf, (state & 0xf0) >> 4);
    man = POS((state & 0xf00) >> 8, (state & 0xf000) >> 12);
    push = ((state & 0x7fff0000) >> 16);
  }
  
  void Input(int w, int h){
    for (int i = 0; i < 20; ++i){
      for (int j = 0; j < 20; ++j){
	TABLE[i][j] = 1;
      }
    }
    for (int y = 2; y <= h + 1; ++y){
      for (int x = 2; x <= w + 1; ++x){
	TABLE[x][y] = 0;
	int in;
	cin >> in;
	if (in == 1){
	  TABLE[x][y] = 1;
	} else if (in == 2){
	  cargo = POS(x, y);
	} else if (in == 3){
	  GOAL = POS(x, y);
	} else if (in == 4){
	  man = POS(x, y);
	}
      }
    }
  }
  bool IsGoal()const{
    return GOAL == cargo;
  }
  int GetState()const{
    int res = 0;
    res |= cargo.real();
    res |= (cargo.imag() << 4);
    res |= (man.real() << 8);
    res |= (man.imag() << 12);
    return res;
  }
  bool CanGo(int dir){
    POS pos1 = man + DIR[dir];
    POS pos2 = man + DIR[dir] * 2;
    if (!TABLE[pos1.real()][pos1.imag()] && cargo != pos1){
      return true;
    }
    if (cargo == pos1 && !TABLE[pos2.real()][pos2.imag()]){
      return true;
    }
    return false;
  }
  void Go(int dir){
    POS pos1 = man + DIR[dir];
    POS pos2 = man + DIR[dir] * 2;
    if (cargo == pos1){
      ++push;
      cargo = pos2;
    }
    man = pos1;
  }
};

int Search(int w, int h)
{
  unsigned int visited[0x10000];
  memset(visited, 0xffffffff, sizeof(visited));
  STATE init;
  init.Input(w, h);

  set<STATE> open;
  open.insert(init);
  visited[init.GetState()] = 0;

  int res = INT_MAX;

  while (!open.empty()){
    //cout << "Search : " << res << endl;
    set<STATE> open2;
    for (set<STATE>::iterator it = open.begin(); it != open.end(); ++it){
      STATE s(*it);
      for (int dir = 0; dir < 4; ++dir){
	if (!s.CanGo(dir)){
	  continue;
	}
	STATE next = s;
	next.Go(dir);
	if (next.push >= visited[next.GetState()]){
	  continue;
	}
	if (next.IsGoal()){
	  res = min(res, next.push);
	  continue;
	}
	open2.insert(next);
	visited[next.GetState()] = next.push;
      }
    }
    swap(open, open2);
  }
  if (res == INT_MAX){
    res = -1;
  }
  return res;
}

main()
{
  int w, h;
  while (cin >> w >> h && !(w == 0 && h == 0)){
    cout << Search(w, h) << endl;
  }
}