W, H = gets.split.map{|i| i.to_i - 1}
Sx, Sy, Gx, Gy = gets.split.map{|i| i.to_i - 1}
Height = $<.read.split.map{|i| i.split('').map &:to_i}

able_to_go = [[Sy, Sx]]

def candidate(ind)
  ary = []
  h = Height[ind[0]][ind[1]]

  ary << [ind[1], ind[0] - 1] if ind[0] > 0 && (Height[ind[1]][ind[0] - 1] - h).abs < 2
  ary << [ind[1], ind[0] + 1] if ind[0] < H && (Height[ind[1]][ind[0] + 1] - h).abs < 2
  ary << [ind[1] - 1, ind[0]] if ind[1] > 0 && (Height[ind[1] - 1][ind[0]] - h).abs < 2
  ary << [ind[1] + 1, ind[0]] if ind[1] < W && (Height[ind[1] + 1][ind[0]] - h).abs < 2

  ary << [ind[1], ind[0] - 2] if ind[0] > 1 && Height[ind[1]][ind[0] - 2] == h && Height[ind[1]][ind[0] - 1] < h
  ary << [ind[1], ind[0] + 2] if ind[0] < H - 1 && Height[ind[1]][ind[0] + 2] == h && Height[ind[1]][ind[0] + 1] < h
  ary << [ind[1] - 2, ind[0]] if ind[1] > 1 && Height[ind[1] - 2][ind[0]] == h && Height[ind[1] - 1][ind[0]] < h
  ary << [ind[1] + 2, ind[0]] if ind[1] < W - 1 && Height[ind[1] + 2][ind[0]] == h && Height[ind[1] + 1][ind[0]] < h
end

def solve
  ((H + 1)*(W + 1)).times{|i|
    return :YES if able_to_go.include?([Gy, Gx])
    return :NO unless (_ = able_to_go[i])
    able_to_go |= candidate(_)
  }
end

puts solve