#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int maxn=510;
int r,c,a[maxn][maxn],f[maxn][maxn];
int dx[5]={0,0,1,-1};
int dy[5]={1,-1,0,0};
int search(int x,int y){
	int xx,yy;
	if(f[x][y])return f[x][y];
	for(int i=0;i<4;i++){
		xx=x+dx[i],yy=y+dy[i];
		if(xx<1 || xx>r || yy<1 || yy>c)continue;
		if(a[x][y]<a[xx][yy])
			f[x][y]=max(f[x][y],search(xx,yy));
	}
	f[x][y]++;
	return f[x][y];
}
int main()
{
	freopen("shunzhi.in","r",stdin);
	freopen("shunzhi.out","w",stdout);
	scanf("%d%d",&r,&c);
	for(int i=1;i<=r;i++){
		for(int j=1;j<=c;j++){
			scanf("%d",&a[i][j]);
		}
	}
	int ans=0;
	for(int i=1;i<=r;i++){
		for(int j=1;j<=c;j++){
			ans=max(ans,search(i,j));
		}
	}
	printf("%d\n",ans);
	return 0;
}