#include <stdio.h>
#include <cmath>
#include <algorithm>
#include <stack>
#include <queue>
#include <vector>
#include <iostream>
typedef long long int ll;
#define BIG_NUM 2000000000
#define MOD 1000000007
#define EPS 0.000000001
using namespace std;

int W,H;
int map[7][7];
int div_row[4] = {-1,0,0,1},div_col[4] = {0,-1,1,0};

struct Info{
	void set(int arg_cargo_row,int arg_cargo_col,int arg_man_row,int arg_man_col,int arg_push_num){
		cargo_row = arg_cargo_row;
		cargo_col = arg_cargo_col;
		man_row = arg_man_row;
		man_col = arg_man_col;
		push_num = arg_push_num;
	}

	int cargo_row,cargo_col,man_row,man_col,push_num;
};

enum LOC{
	UE,
	SHITA,
	MIGI,
	HIDARI,
};

bool rangeCheck(int row,int col){
	if(row >= 0 && row <= H-1 && col >= 0 && col <= W-1)return true;
	else{
		return false;
	}
}

void recursive(int distance[7][7],int row,int col,int to_row,int to_col){
	for(int i = 0; i < 4; i++){
		int next_row = row+div_row[i],next_col = col+div_col[i];
		if(rangeCheck(next_row,next_col) == true && map[next_row][next_col] != 1 && distance[next_row][next_col] > distance[row][col]+1){
			distance[next_row][next_col] = distance[row][col]+1;
			if(next_row == to_row && next_col == to_col)return;
			recursive(distance,next_row,next_col,to_row,to_col);
		}
	}
}

bool isMoveable(int cargo_row,int cargo_col,LOC current_loc,LOC to_loc){ //curent_loc:???????????¨??° to_loc:???????????????

	int distance[7][7];
	for(int i = 0; i < 7; i++){
		for(int k = 0; k < 7; k++){
			distance[i][k] = BIG_NUM;
		}
	}

	switch(current_loc){
	case UE:

		distance[cargo_row][cargo_col] = -1;
		distance[cargo_row-1][cargo_col] = 0;

		switch(to_loc){
		case MIGI:
			if(rangeCheck(cargo_row,cargo_col+1) == false || map[cargo_row][cargo_col+1] == 1)return false;

			recursive(distance,cargo_row-1,cargo_col,cargo_row,cargo_col+1);

			if(distance[cargo_row][cargo_col+1] != BIG_NUM)return true;

			break;
		case HIDARI:
			if(rangeCheck(cargo_row,cargo_col-1) == false || map[cargo_row][cargo_col-1] == 1)return false;

			recursive(distance,cargo_row-1,cargo_col,cargo_row,cargo_col-1);

			if(distance[cargo_row][cargo_col-1] != BIG_NUM)return true;

			break;
		case SHITA:
			if(rangeCheck(cargo_row+1,cargo_col) == false || map[cargo_row+1][cargo_col] == 1)return false;

			recursive(distance,cargo_row-1,cargo_col,cargo_row+1,cargo_col);

			if(distance[cargo_row+1][cargo_col] != BIG_NUM)return true;

			break;
		}
		break;
	case SHITA:

		distance[cargo_row][cargo_col] = -1;
		distance[cargo_row+1][cargo_col] = 0;

		switch(to_loc){
		case MIGI:
			if(rangeCheck(cargo_row,cargo_col+1) == false || map[cargo_row][cargo_col+1] == 1)return false;

			recursive(distance,cargo_row+1,cargo_col,cargo_row,cargo_col+1);

			if(distance[cargo_row][cargo_col+1] != BIG_NUM)return true;
			break;
		case HIDARI:
			if(rangeCheck(cargo_row,cargo_col-1) == false || map[cargo_row][cargo_col-1] == 1)return false;

			recursive(distance,cargo_row+1,cargo_col,cargo_row,cargo_col-1);

			if(distance[cargo_row][cargo_col-1] != BIG_NUM)return true;
			break;
		case UE:
			if(rangeCheck(cargo_row-1,cargo_col) == false || map[cargo_row-1][cargo_col] == 1)return false;

			recursive(distance,cargo_row+1,cargo_col,cargo_row-1,cargo_col);

			if(distance[cargo_row-1][cargo_col] != BIG_NUM)return true;
			break;
		}
		break;
	case MIGI:

		distance[cargo_row][cargo_col] = -1;
		distance[cargo_row][cargo_col+1] = 0;

		switch(to_loc){
		case UE:
			if(rangeCheck(cargo_row-1,cargo_col) == false || map[cargo_row-1][cargo_col] == 1)return false;

			recursive(distance,cargo_row,cargo_col+1,cargo_row-1,cargo_col);

			if(distance[cargo_row-1][cargo_col] != BIG_NUM)return true;
			break;
		case SHITA:
			if(rangeCheck(cargo_row+1,cargo_col) == false || map[cargo_row+1][cargo_col] == 1)return false;

			recursive(distance,cargo_row,cargo_col+1,cargo_row+1,cargo_col);

			if(distance[cargo_row+1][cargo_col] != BIG_NUM)return true;
			break;
		case HIDARI:
			if(rangeCheck(cargo_row,cargo_col-1) == false || map[cargo_row][cargo_col-1] == 1)return false;

			recursive(distance,cargo_row,cargo_col+1,cargo_row,cargo_col-1);

			if(distance[cargo_row][cargo_col-1] != BIG_NUM)return true;
			break;
		}
		break;
	case HIDARI:

		distance[cargo_row][cargo_col] = -1;
		distance[cargo_row][cargo_col-1] = 0;

		switch(to_loc){
		case UE:
			if(rangeCheck(cargo_row-1,cargo_col) == false || map[cargo_row-1][cargo_col] == 1)return false;

			recursive(distance,cargo_row,cargo_col-1,cargo_row-1,cargo_col);

			if(distance[cargo_row-1][cargo_col] != BIG_NUM)return true;
			break;
		case SHITA:
			if(rangeCheck(cargo_row+1,cargo_col) == false || map[cargo_row+1][cargo_col] == 1)return false;

			recursive(distance,cargo_row,cargo_col-1,cargo_row+1,cargo_col);

			if(distance[cargo_row+1][cargo_col] != BIG_NUM)return true;
			break;
		case MIGI:
			if(rangeCheck(cargo_row,cargo_col+1) == false || map[cargo_row][cargo_col+1] == 1)return false;

			recursive(distance,cargo_row,cargo_col-1,cargo_row,cargo_col+1);

			if(distance[cargo_row][cargo_col+1] != BIG_NUM)return true;
			break;
		}
		break;
	}
	return false;
}

void func(){

	int c_start_row,c_start_col,m_start_row,m_start_col;

	for(int i = 0; i < H; i++){
		for(int k = 0; k < W; k++){
			scanf("%d",&map[i][k]);
			if(map[i][k] == 2){
				c_start_row = i;
				c_start_col = k;
			}else if(map[i][k] == 4){
				m_start_row = i;
				m_start_col = k;
			}
		}
	}

	bool relativePos[H][W][H][W];

	for(int i = 0; i < H; i++){
		for(int k = 0; k < W; k++){
			for(int a = 0; a < H; a++){
				for(int b = 0; b < W; b++)relativePos[i][k][a][b] = false;
			}
		}
	}

	int first_row,first_col;
	int distance[7][7];

	queue<Info> Q;

	for(int i = 0; i < 4; i++){
		first_row = c_start_row+div_row[i];
		first_col = c_start_col+div_col[i];
		if(rangeCheck(first_row,first_col) == true && map[first_row][first_col] != 1){
			for(int a = 0; a < H; a++){
				for(int b = 0; b < W; b++){
					distance[a][b] = BIG_NUM;
				}
			}
			distance[m_start_row][m_start_col] = 0;
			distance[c_start_row][c_start_col] = -1;
			recursive(distance,m_start_row,m_start_col,first_row,first_col);
			if(distance[first_row][first_col] != BIG_NUM){
				Info first;
				first.set(c_start_row,c_start_col,first_row,first_col,0);
				relativePos[c_start_row][c_start_col][first_row][first_col] = true;
				Q.push(first);
			}
		}
	}

	Info current;
	int ans = -1,next_row,next_col;
	LOC nowLoc;

	while(!Q.empty()){
		current = Q.front();
		Q.pop();

		if(map[current.cargo_row][current.cargo_col] == 3){
			ans = current.push_num;
			break;
		}

		if(current.cargo_row == current.man_row){
			if(current.cargo_col > current.man_col){
				nowLoc = HIDARI;
			}else{
				nowLoc = MIGI;
			}
		}else{
			if(current.cargo_row > current.man_row){
				nowLoc = UE;
			}else{
				nowLoc = SHITA;
			}
		}

		for(int i = 0; i < 4; i++){
			next_row = current.cargo_row+div_row[i];
			next_col = current.cargo_col+div_col[i];
			if(rangeCheck(next_row,next_col) == true && map[next_row][next_col] != 1 && relativePos[next_row][next_col][current.cargo_row][current.cargo_col] == false){

				Info new_info;

				switch(nowLoc){
				case UE:
					switch(i){
					case 0:
						if(isMoveable(current.cargo_row,current.cargo_col,UE,SHITA)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					case 1:
						if(isMoveable(current.cargo_row,current.cargo_col,UE,MIGI)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					case 2:
						if(isMoveable(current.cargo_row,current.cargo_col,UE,HIDARI)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					case 3:
						new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
						relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
						Q.push(new_info);
						break;
					}
					break;
				case SHITA:
					switch(i){
					case 0:

						new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
						relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
						Q.push(new_info);
						break;
					case 1:
						if(isMoveable(current.cargo_row,current.cargo_col,SHITA,MIGI)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					case 2:
						if(isMoveable(current.cargo_row,current.cargo_col,SHITA,HIDARI)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					case 3:
						if(isMoveable(current.cargo_row,current.cargo_col,SHITA,UE)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					}
					break;
				case MIGI:
					switch(i){
					case 0:
						if(isMoveable(current.cargo_row,current.cargo_col,MIGI,SHITA)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					case 1:
						new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
						Q.push(new_info);
						break;
					case 2:
						if(isMoveable(current.cargo_row,current.cargo_col,MIGI,HIDARI)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					case 3:
						if(isMoveable(current.cargo_row,current.cargo_col,MIGI,UE)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					}
					break;
				case HIDARI:
					switch(i){
					case 0:
						if(isMoveable(current.cargo_row,current.cargo_col,HIDARI,SHITA)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					case 1:
						if(isMoveable(current.cargo_row,current.cargo_col,HIDARI,MIGI)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					case 2:
						new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
						relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
						Q.push(new_info);
						break;
					case 3:
						if(isMoveable(current.cargo_row,current.cargo_col,HIDARI,UE)){

							new_info.set(next_row,next_col,current.cargo_row,current.cargo_col,current.push_num+1);
							relativePos[next_row][next_col][current.cargo_row][current.cargo_col] = true;
							Q.push(new_info);
						}
						break;
					}
					break;
				}
			}
		}

	}

	printf("%d\n",ans);

}

int main(){

	while(true){
		scanf("%d %d",&W,&H);
		if(W == 0 && H == 0)break;

		func();
	}

	return 0;
}

Measured memory_bytes: 3204