#include<cstdio>
#define Cu fclose(stdin);fclose(stdout);return 0;
#define Begin freopen("shunzhi.in","r",stdin);freopen("shunzhi.out","w",stdout);chul();Cu;
using namespace std;
const int maxn=510;
int ans=0;int x,y;
int w[maxn][maxn],f[maxn][maxn];
int max(int,int);
int dp(int,int);
void chul();
int main(){
	Begin;
	chul();
}
void chul(){
	scanf("%d%d",&x,&y);
	for(int i=1;i<=x;i++){
		for(int j=1;j<=y;j++)
			scanf("%d",&w[i][j]);
	}
	for(int i=1;i<=x;i++){
		for(int j=1;j<=y;j++){
			dp(i,j);
		}
	}
	printf("%d",ans);
}
int dp(int i,int j){
	if(f[i][j]>0)return f[i][j];
	bool flag=0;
	if(w[i+1][j]>w[i][j]){
		flag=1;
		f[i][j]=max(f[i][j],dp(i+1,j)+1);
	}
	if(w[i-1][j]>w[i][j]){
		flag=1;
		f[i][j]=max(f[i][j],dp(i-1,j)+1);
	}
	if(w[i][j-1]>w[i][j]){
		flag=1;
		f[i][j]=max(f[i][j],dp(i,j-1)+1);
	}
	if(w[i][j+1]>w[i][j]){
		flag=1;
		f[i][j]=max(f[i][j],dp(i,j+1)+1);
	}
	if(!flag){
		f[i][j]=1;
	}
	ans=max(ans,f[i][j]);
	return f[i][j];
}
int max(int x,int y){
	if(x>y)return x;
	return y;
}