#include <bits/stdc++.h>
using namespace std;
int n,m,x,y,ans=1;
int a[110][110];
int dx[5]={0,0,1,-1,0};
int dy[5]={0,1,0,0,-1};
void bfs(int x,int y){
	int qx[10010],qy[10010],qs[10010];
	memset(qx,0,sizeof(qx));
	memset(qy,0,sizeof(qy));
	memset(qs,0,sizeof(qs));
	int head=0,tail=1,tx,ty,ts;
	qx[tail]=x;
	qy[tail]=y;
	qs[tail]=1;
	while(head!=tail){
		head++;
		tx=qx[head];
		ty=qy[head];
		ts=qs[head];
		for(int i=1;i<=4;i++){
			x=tx+dx[i];
			y=ty+dy[i];
			if(x<1||y<1||x>n||y>m) continue;
			if(a[x][y]>=a[tx][ty]) continue;
			tail++;
			qx[tail]=x;
			qy[tail]=y;
			qs[tail]=ts+1;
			ans=max(ans,qs[tail]);
		}
	}
	return ;
}
int main(){
	cin>>n>>m;
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++)
			cin>>a[i][j];
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++)
			bfs(i,j);
	cout<<ans<<endl;
	return 0;
}