import sys
sys.setrecursionlimit(10**6)

h, w = map(int, input().split())
s_x, s_y, g_x, g_y = map(int, input().split())
s = [s_x-1, s_y-1]
g = [g_x-1, g_y-1]
b = [list(map(int, input())) for _ in range(h)]
flg = [[False for _ in range(w)] for _ in range(h)]

def judge(cx,cy,nx,ny):
	ch = b[cx][cy]
	nh = b[nx][ny]

	if abs(cx+cy-nx-ny) == 1:
		if abs(ch-nh) <= 1:
			return True

	elif abs(cx+cy-nx-ny) == 2:
		mh = b[(cx+nx)//2][(cy+ny)//2]
		if mh < ch and mh < nh and ch == nh:
			return True

def bfs(q):
	cx,cy = q.pop(0)

	next = [[cx+1, cy],[cx-1, cy],[cx, cy+1],[cx, cy-1],[cx+2, cy],[cx-2, cy],[cx, cy+2],[cx, cy-2]]
	for nx, ny in next:
		if 0 <= nx < h and 0 <= ny < w and flg[nx][ny] == False:
			if judge(cx, cy, nx, ny):
				flg[nx][ny] = True
				q.append([nx, ny])

	if len(q) == 0:
		return flg[g[0]][g[1]]

	return bfs(q)

q = []
q.append(s)

if bfs(q):
	print("YES")
else:
	print("NO")