import macros;macro ImportExpand(s:untyped):untyped = parseStmt($s[2])
ImportExpand "cplib/tmpl/sheep.nim" <=== "when not declared CPLIB_TMPL_SHEEP:\n    const CPLIB_TMPL_SHEEP* = 1\n    {.warning[UnusedImport]: off.}\n    {.hint[XDeclaredButNotUsed]: off.}\n    import algorithm\n    import sequtils\n    import tables\n    import macros\n    import math\n    import sets\n    import strutils\n    import strformat\n    import sugar\n    import heapqueue\n    import streams\n    import deques\n    import bitops\n    import std/lenientops\n    import options\n    #入力系\n    proc scanf(formatstr: cstring){.header: \"<stdio.h>\", varargs.}\n    proc getchar(): char {.importc: \"getchar_unlocked\", header: \"<stdio.h>\", discardable.}\n    proc ii(): int {.inline.} = scanf(\"%lld\\n\", addr result)\n    proc lii(N: int): seq[int] {.inline.} = newSeqWith(N, ii())\n    proc si(): string {.inline.} =\n        result = \"\"\n        var c: char\n        while true:\n            c = getchar()\n            if c == ' ' or c == '\\n':\n                break\n            result &= c\n    #chmin,chmax\n    template `max=`(x, y) = x = max(x, y)\n    template `min=`(x, y) = x = min(x, y)\n    #bit演算\n    proc `%`(x: int, y: int): int = (((x mod y)+y) mod y)\n    proc `//`(x: int, y: int): int = (((x) - (x%y)) div (y))\n    proc `%=`(x: var int, y: int): void = x = x%y\n    proc `//=`(x: var int, y: int): void = x = x//y\n    proc `**`(x: int, y: int): int = x^y\n    proc `^`(x: int, y: int): int = x xor y\n    proc `|`(x: int, y: int): int = x or y\n    proc `&`(x: int, y: int): int = x and y\n    proc `>>`(x: int, y: int): int = x shr y\n    proc `<<`(x: int, y: int): int = x shl y\n    proc `^=`(x: var int, y: int): void = x = x ^ y\n    proc `&=`(x: var int, y: int): void = x = x & y\n    proc `|=`(x: var int, y: int): void = x = x | y\n    proc `>>=`(x: var int, y: int): void = x = x >> y\n    proc `<<=`(x: var int, y: int): void = x = x << y\n    proc `[]`(x: int, n: int): bool = (x and (1 shl n)) != 0\n    proc `@`(x: int): seq[int] =\n        for i in 0..<64:\n            if x[i]:\n                result.add(i)\n    #便利な変換\n    proc `!`(x: char, a = '0'): int = int(x)-int(a)\n    #定数\n    const INF = int(3300300300300300491)\n    #converter\n\n    #range\n    iterator range(start: int, ends: int, step: int): int =\n        var i = start\n        if step < 0:\n            while i > ends:\n                yield i\n                i += step\n        elif step > 0:\n            while i < ends:\n                yield i\n                i += step\n    iterator range(ends: int): int = (for i in 0..<ends: yield i)\n    iterator range(start: int, ends: int): int = (for i in\n            start..<ends: yield i)\n"
ImportExpand "cplib/collections/segtree.nim" <=== "when not declared CPLIB_COLLECTIONS_SEGTREE:\n    const CPLIB_COLLECTIONS_SEGTREE* = 1\n    import algorithm\n    type SegmentTree*[T] = ref object\n        default: T\n        merge: proc(x: T, y: T): T\n        arr*: seq[T]\n        lastnode: int\n        length: int\n    proc initSegmentTree*[T](v: seq[T], merge: proc(x: T, y: T): T, default: T): SegmentTree[T] =\n        ## セグメントツリーを生成します。\n        ## vに元となるリスト、mergeに二つの区間をマージする関数、デフォルトに単位元を与えてください。\n        var lastnode = 1\n        while lastnode < len(v):\n            lastnode*=2\n        var arr = newSeq[T](2*lastnode)\n        arr.fill(default)\n        var self = SegmentTree[T](default: default, merge: merge, arr: arr, lastnode: lastnode, length: len(v))\n        #1-indexedで作成する\n        for i in 0..<len(v):\n            self.arr[self.lastnode+i] = v[i]\n        for i in countdown(lastnode-1, 1):\n            self.arr[i] = self.merge(self.arr[2*i], self.arr[2*i+1])\n        return self\n\n    proc update*[T](self: SegmentTree[T], x: Natural, val: T) =\n        ## xの要素をvalに変更します。\n        assert x < self.length\n        var x = x\n        x += self.lastnode\n        self.arr[x] = val\n        while x > 1:\n            x = x shr 1\n            self.arr[x] = self.merge(self.arr[2*x], self.arr[2*x+1])\n    proc get*[T](self: SegmentTree[T], q_left: Natural, q_right: Natural): T =\n        ## 半解区間[q_left,q_right)についての演算結果を返します。\n        assert q_left <= q_right and 0 <= q_left and q_right <= self.length\n        var q_left = q_left\n        var q_right = q_right\n        q_left += self.lastnode\n        q_right += self.lastnode\n        var (lres, rres) = (self.default, self.default)\n        while q_left < q_right:\n            if (q_left and 1) > 0:\n                lres = self.merge(lres, self.arr[q_left])\n                q_left += 1\n            if (q_right and 1) > 0:\n                q_right -= 1\n                rres = self.merge(self.arr[q_right], rres)\n            q_left = q_left shr 1\n            q_right = q_right shr 1\n        return self.merge(lres, rres)\n    proc get*[T](self: SegmentTree[T], segment: HSlice[int, int]): T =\n        assert segment.a <= segment.b + 1 and 0 <= segment.a and segment.b+1 <= self.length\n        return self.get(segment.a, segment.b+1)\n    proc `[]`*[T](self: SegmentTree[T], index: Natural): T =\n        assert index < self.length\n        return self.arr[index+self.lastnode]\n    proc `[]=`*[T](self: SegmentTree[T], index: Natural, val: T) =\n        assert index < self.length\n        self.update(index, val)\n    proc get_all*[T](self: SegmentTree[T]): T =\n        ## [0,len(self))区間の演算結果をO(1)で返す\n        return self.arr[1]\n    proc len*[T](self: SegmentTree[T]): int =\n        return self.length\n\n    template newSegWith*(V, merge, default: untyped): untyped =\n        initSegmentTree(V, (l, r{.inject.}: typeof(default)) => merge, default)\n\n"
var H,W = ii()
var A = newseqwith(H,newSeqWith(W,ii()))
var X : seq[(int,int,int)]
for i in range(H):
    for j in range(W):
        X.add (A[i][j],i,j)
X.sort()
var DP = newseqwith(H,newSeqWith(W,-INF))

for (a,i,j) in X:
    DP[i][j] = 1
    for (di,dj) in [(0,1),(1,0),(-1,0),(0,-1)]:
        if i+di in 0..<H and j+dj in 0..<W and A[i][j] > A[i+di][j+dj]:
            DP[i][j].max = DP[i+di][j+dj] + 1

echo DP.mapit(max(it)).max()