#!/usr/bin/python

from collections import deque

h,w = map(int, raw_input().split())
a,si,sj = map(int,raw_input().split())
b,gi,gj = map(int,raw_input().split())
m = [raw_input() for i in range(h)]

ma = max(a+h+w-1,b+2*(h+w))

dist = [[[1<<29] * (ma+1) for j in range(w)] for i in range(h)]

d = [0,1,0,-1]

q = deque([a << 16 | si << 8 | sj]);
dist[si][sj][a] = 0
while len(q) > 0:
    p = q.popleft()
    cs = p >> 16
    ci = p >> 8 & 0xff
    cj = p & 0xff
    for i in range(4):
        ni = ci + d[i]
	nj = cj + d[i^1]
	if ni < 0 or ni >= h or nj < 0 or nj >= w :
	    continue
	ns = cs + (1 if m[ni][nj] == '*' else -1)
	if ns > ma or ns <= 0 or dist[ni][nj][ns] <= dist[ci][cj][cs] + 1:
	    continue
	dist[ni][nj][ns] = dist[ci][cj][cs] + 1
	q.append(ns << 16 | ni << 8 | nj)
print(-1 if dist[gi][gj][b] >= 1 << 29 else dist[gi][gj][b])