import java.util.*;

public class Main
{
	static int max = 0;
	static int depthMax = 0;
	
	public static void main(String args[])
	{
		Scanner cin = new Scanner(System.in);
		int aa = cin.nextInt();
		int bb = cin.nextInt();
		
		
		int height[][] = new int[aa][bb];
		
		for (int i=0;i<aa;i++)
			for (int j=0;j<bb;j++)
				height[i][j] = cin.nextInt();

		for (int i=0;i<aa;i++)
		{
			for (int j=0;j<bb;j++)
			{
				depthMax = 0;
				next(height,i,j);
			}
		}
		
		System.out.println(max);
	}
	
	public static void next(int[][] data,int a,int b)
	{
		if (max == data.length*data[a].length)
			System.exit(0);
		
		depthMax++;	
		
		if (goLeft(data,a,b))
			next(data,a,b-1);
		
		if (goRight(data,a,b))
			next(data,a,b+1);

		if (goUp(data,a,b))
			next(data,a-1,b);
		
		if (goDown(data,a,b))
			next(data,a+1,b);

		if (max < depthMax)
			max = depthMax;
		
		depthMax--;
	}
	
	public static boolean goLeft(int[][] data,int a,int b)
	{
		if (b<=0)
			return false;
		if (data[a][b-1] < data[a][b])
			return true;
		else return false;
	}
	
	public static boolean goRight(int[][] data,int a,int b)
	{
		if (b>=data[0].length-1)
			return false;
		if (data[a][b+1] < data[a][b])
			return true;
		else return false;

	}
	
	public static boolean goUp(int[][] data,int a,int b)
	{
		if (a<=0)
			return false;
		if (data[a-1][b] < data[a][b])
			return true;
		else return false;
	}
	
	public static boolean goDown(int[][] data,int a,int b)
	{
		if (a>=data.length-1)
			return false;
		if (data[a+1][b] < data[a][b])
			return true;
		else return false;
	}
}