h,w=gets.split.map(&:to_i)
sx,sy,gx,gy=gets.split.map{|s|s.to_i-1}
maze=h.times.map{gets.chomp.bytes.to_a}

init_state=[sx,sy]
q=[init_state]
visited={}

until q.empty?
	curr_state=q.shift
	next if visited[curr_state]
	visited[curr_state]=true
	if curr_state==[gx,gy]
		puts "YES"
		exit
	end
	height=maze.dig(*curr_state)
	x,y=curr_state
	[
		[[[1,0],[0,1],[-1,0],[0,-1]],1],
		[[[2,0],[0,2],[-2,0],[0,-2]],0]
	].each{|directions,threshold|
		directions.each{|dx,dy|
			nx,ny=x+dx,y+dy
			next unless (0...h)===nx
			next unless (0...w)===ny
			next_state=[nx,ny]
			next unless (maze.dig(*next_state)-height).abs<=threshold
			q.push next_state
		}
	}
end

puts "NO"