import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.buffer.readline())
def LI(): return list(map(int, sys.stdin.buffer.readline().split()))
def LI1(): return list(map(int1, sys.stdin.buffer.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def BI(): return sys.stdin.buffer.readline().rstrip()
def SI(): return sys.stdin.buffer.readline().rstrip().decode()
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = 10**16
# md = 998244353
md = 10**9+7

from collections import deque

move = [[1, 5, 3, 4],
        [2, 1, 0, 1],
        [3, 4, 1, 5],
        [0, 3, 2, 3],
        [4, 0, 4, 2],
        [5, 2, 5, 0]]

h, w = LI()
si, sj = LI1()
gi, gj = LI1()
gij = gi*w+gj
aa = [a == "." for _ in range(h) for a in SI()]

dp = [[-1]*6 for _ in range(h*w)]
q = deque()
q.append((si*w+sj, 0))
dp[si*w+sj][0] = 0

def push(nij, dir):
    ns = move[s][dir]
    if nij == gij and ns == 0:
        print(dist+1)
        exit()
    if dp[nij][ns] == -1 and aa[nij]:
        q.append((nij, ns))
        dp[nij][ns] = dist+1

while q:
    ij, s = q.popleft()
    i, j = divmod(ij, w)
    dist = dp[ij][s]
    if i: push(ij-w, 1)
    if i+1 < h: push(ij+w, 3)
    if j: push(ij-1, 2)
    if j+1 < w: push(ij+1, 0)

print(-1)