type UnionFind(n) =
    let n = n
    let parent = [| 0 .. n - 1|]

    member this.Parent with get() = parent

    member this.Find x = 
        if this.Parent.[x] <> x then
            this.Parent.[x] <- this.Find this.Parent.[x]
        this.Parent.[x]

    member this.Unite x y =
        this.Parent.[this.Find x] <- this.Find y

    member this.Same x y = (this.Find x) = (this.Find y)

let h, w = System.Console.ReadLine().Split() |> Array.map int |> fun a -> a.[0], a.[1]
let sy, sx, gy, gx = System.Console.ReadLine().Split() |> Array.map int |> Array.map ((+) -1) |> fun a -> a.[0], a.[1], a.[2], a.[3]

let b = [|for i in 0 .. h - 1 -> System.Console.ReadLine().ToCharArray() |> Array.map int|]

let uf = new UnionFind(h * w)

for i = 0 to h - 1 do
    for j = 0 to w - 1 do
        for di, dj in [(0, 1); (1, 0); (0, -1); (-1, 0)] do
            let ii = i + di
            let jj = j + dj
            if 0 <= ii && ii < h && 0 <= jj && jj < w then
                if abs (b.[ii].[jj] - b.[i].[j]) <= 1 then
                    uf.Unite (i * w + j) (ii * w + jj)
        for di, dj in [(0, 1); (1, 0); (0, -1); (-1, 0)] do
            let ii = i + di
            let jj = j + dj
            let iii = i + di * 2
            let jjj = j + dj * 2
            if 0 <= iii && iii < h && 0 <= jjj && jjj < w then
                if b.[ii].[jj] < b.[i].[j] && b.[iii].[jjj] = b.[i].[j] then
                    uf.Unite (i * w + j) (iii * w + jjj)

if uf.Same (sy * w + sx) (gy * w + gx) then "YES" else "NO"
|> System.Console.WriteLine