# Here your code !
G = Hash.new{|h,k| h[k] = []}

def dfs(s,t,size)
    used = Array.new(size)
    stack = [s]
    until stack.empty?
        v = stack.pop
        used[v] = true
        if v == t
            break
        end
        
        G[v].reject {|u| used[u] }.each do |u| 
            stack << u
        end
    end
    used[t]
end

h,w = gets.split.map(&:to_i)
sy, sx, gy, gx = gets.split.map(&:to_i).map {|v| v - 1}
map = h.times.map do 
    gets.chomp.chars.map(&:to_i)
end

h.times do |y|
    w.times.each_cons(2) do |a,b|
        if (map[y][a] - map[y][b]).abs <= 1
            G[y * w + a] << y * w + b
            G[y * w + b] << y * w + a
        end
    end
    w.times.each_cons(3) do |a,b,c|
        if map[y][a] == map[y][c] && map[y][a] > map[y][b]
            G[y * w + a] << y * w + c
            G[y * w + c] << y * w + a
        end
    end
end
w.times do |x|
    h.times.each_cons(2) do |a,b|
        if (map[a][x] - map[b][x]).abs <= 1
            G[a * w + x] << b * w + x
            G[b * w + x] << a * w + x
        end
    end
    h.times.each_cons(3) do |a,b,c|
        if map[a][x] == map[c][x] && map[a][x] > map[b][x]
            G[a * w + x] << c * w + x
            G[c * w + x] << a * w + x
        end
    end
end

puts dfs(w * sy + sx, w * gy + gx, h * w) ? "YES" : "NO"