"""

https://yukicoder.me/problems/no/1572

サイコロの向きは、6通りしかない
頑張って推移を書けばおk

0 表
1 上
2 右
3 下
4 左
5 裏

"""

import sys
from sys import stdin
from collections import deque

def encode(x,y,state):
    return H*W*state + y*H + x

def decode(now):
    state = now // (H*W)
    y = (now % (H*W)) // H
    x = (now % (H*W)) % H
    return x,y,state

def chdi(state,movedir):

    if state == 0:
        if movedir == "U":
            return 1
        elif movedir == "R":
            return 2
        elif movedir == "D":
            return 3
        else:
            return 4

    elif state == 1: #上
        if movedir == "U":
            return 5
        elif movedir == "D":
            return 0
        else:
            return 1

    elif state == 2: #右
        if movedir == "R":
            return 5
        elif movedir == "L":
            return 0
        else:
            return 2

    elif state == 3: #下
        if movedir == "D":
            return 5
        elif movedir == "U":
            return 0
        else:
            return 3

    elif state == 4: #左
        if movedir == "L":
            return 5
        elif movedir == "R":
            return 0
        else:
            return 4

    else: #裏
        if movedir == "U":
            return 3
        elif movedir == "R":
            return 4
        elif movedir == "D":
            return 1
        else:
            return 2
    

H,W = map(int,stdin.readline().split())

sx,sy = map(int,stdin.readline().split())
gx,gy = map(int,stdin.readline().split())
sx -= 1
sy -= 1
gx -= 1
gy -= 1

A = [ list(stdin.readline()[:-1]) for i in range(H) ]
d = [float("inf")] * (H*W*6)

q = deque([encode(sx,sy,0)])
d[encode(sx,sy,0)] = 0

while q:

    code = q.popleft()
    x,y,state = decode(code)

    if x != 0 and A[x-1][y] != "#":
        nx,ny,nstate = x-1,y,chdi(state,"U")
        ncode = encode(nx,ny,nstate)

        if d[ncode] > d[code] + 1:
            d[ncode] = d[code] + 1
            q.append(ncode)

    if x != H-1 and A[x+1][y] != "#":
        nx,ny,nstate = x+1,y,chdi(state,"D")
        ncode = encode(nx,ny,nstate)

        if d[ncode] > d[code] + 1:
            d[ncode] = d[code] + 1
            q.append(ncode)

    if y != 0 and A[x][y-1] != "#":
        nx,ny,nstate = x,y-1,chdi(state,"L")
        ncode = encode(nx,ny,nstate)

        if d[ncode] > d[code] + 1:
            d[ncode] = d[code] + 1
            q.append(ncode)

    if y != W-1 and A[x][y+1] != "#":
        nx,ny,nstate = x,y+1,chdi(state,"R")
        ncode = encode(nx,ny,nstate)

        if d[ncode] > d[code] + 1:
            d[ncode] = d[code] + 1
            q.append(ncode)

ans = d[encode(gx,gy,0)]
print (ans if ans != float("inf") else -1)