#include <iostream>
#include<queue>
#include<string.h>
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;

struct xun
{
	int i=0,j=0,num=0;
};

struct cmp1
{
	bool operator()(const xun a,const xun b)
	{
		return a.num>b.num;
	}
};

priority_queue<xun,vector<xun>,cmp1>q;

int z[102][102]={};
int total[102][102]={};


int main(int argc, char** argv) {
	
	memset(total,0,sizeof(total));
	
	for(int i=1;i<=101;i++)
	for(int j=1;j<=101;j++)
	total[i][j]=1;
	
	
	int a,b;
	cin>>a>>b;
	
	for(int i=1;i<=b;i++)
	for(int j=1;j<=a;j++)
	{
		xun asa;
		cin>>asa.num;
		
		z[i][j]=asa.num;
		
		asa.i=i;
		asa.j=j;
		q.push(asa);
	}
	
	while(!q.empty())
	{
		xun p=q.top();
		int i=p.i;
		int j=p.j;
		int num=p.num;
		q.pop();
		
		if( num>z[i-1][j]   )total[i][j]=max(total[i-1][j]+1,total[i][j]);
		if( num>z[i+1][j]   )total[i][j]=max(total[i+1][j]+1,total[i][j]);
		if( num>z[i][j+1]   )total[i][j]=max(total[i][j+1]+1,total[i][j]);
		if( num>z[i][j-1]   )total[i][j]=max(total[i][j-1]+1,total[i][j]);
	}
	
	int xunxas=-1;
	
	for(int i=1;i<=b;i++)
	for(int j=1;j<=a;j++)
	xunxas=max(xunxas,total[i][j]);
	
	cout<<xunxas;
	
	
	return 0;
}