package poj;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Scanner;
public class Main1088_1 {
static class Node implements Comparable<Node> {
int x;
int y;
int height;
@Override
public int compareTo(Node o) {
if (height > o.height)
return 1;
else if (height < o.height)
return -1;
else
return 0;
}
}
public static void main(String[] args) throws FileNotFoundException {
Scanner scanner = new Scanner(new BufferedInputStream(
new FileInputStream(new File("E:\\input.txt"))));
int r = scanner.nextInt();
int c = scanner.nextInt();
int[][] arr = new int[r][c];
int[][] res = new int[r][c];
Node[] list = new Node[r * c];
int t = 0;
for (int i = 0; i < r; i++) {
for (int j = 0; j < c; j++) {
arr[i][j] = scanner.nextInt();
list[t] = new Node();
list[t].x = i;
list[t].y = j;
list[t++].height = arr[i][j];
}
}
Arrays.sort(list);
int ans=0;
for (int i = 0; i < list.length; i++) {
int x = list[i].x;
int y = list[i].y;
int h = list[i].height;
if (x - 1 >= 0 && arr[x - 1][y] > h&&res[x-1][y]<res[x][y]+1)
res[x - 1][y]=res[x][y] + 1;// left
if (x + 1 < r && arr[x + 1][y] > h&&res[x+1][y]<res[x][y]+1)
res[x + 1][y]=res[x][y] + 1;// right
if (y - 1 >= 0 && arr[x][y - 1] > h&&res[x][y-1]<res[x][y]+1)
res[x][y - 1] =res[x][y] + 1;// up
if (y + 1 < c && arr[x][y + 1] > h&&res[x][y+1]<res[x][y]+1)
res[x][y + 1]=res[x][y] + 1;// down
if (ans<res[x][y]) ans=res[x][y];
}
System.out.println(ans+1);
}
}