#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
const int N = 310;
int map[N][N];
int f[N][N];
int n,m,res;
int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};
int dfs(int x,int y){
if(f[x][y]!=-1) return f[x][y];
f[x][y]=1;
for (int i = 0; i <= 3; i ++ ){
int seex=x+dx[i];
int seey=y+dy[i];
if(seex>0&&seex<=n&&seey>0&&seey<=m&&map[x][y]>map[seex][seey]){
f[x][y]=max(f[x][y],dfs(seex,seey)+1);
}
}
return f[x][y];
}
int main()
{
cin>>n>>m;
memset(f, -1, sizeof f);
for (int i = 1; i <= n; i ++ )
for (int j = 1; j <= m; j ++ )
cin>>map[i][j];
for (int i = 1; i <= n; i ++ )
for (int j = 1; j <= m; j ++ )
res=max(res,dfs(i,j));
cout<<res;
return 0;
}