#include<iostream>
using namespace std;
int a[105][105],len[105][105]; 
int max(int a,int b,int c,int d)
{if(a<b)
    a=b;
if(a<c)
	a=c;
if(a<d)
	a=d;
return a;}
int dfs(int p,int q,int h)
{if(a[p][q]==0||a[p][q]>h)
    return 0;
if(len[p][q]>=0)
	return len[p][q];
len[p][q]=max(dfs(p-1,q,a[p][q]),dfs(p,q+1,a[p][q]),dfs(p+1,q,a[p][q]),dfs(p,q-1,a[p][q]))+1;
    return len[p][q];
}
int main()
{int i,j,x,y,max;
while(cin>>x>>y)
{memset(a,0,sizeof(a));
memset(len,0,sizeof(len));
for(i=0;i<x;i++)
  for(j=0;j<y;j++)
	{cin>>a[i][j];
len[i][j]=-1;}
max=0;
for(i=0;i<x;i++)
  for(j=0;j<y;j++)
	  {len[i][j]=dfs(i,j,a[i][j]);
       if(len[i][j]>max)
		   max=len[i][j];}
cout<<max<<endl;}
return 0;
}