#include<iostream>
#include<queue>
using namespace std;
short int r,c;
struct sb{
    short int x,y;
};
short int fl[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
short int a[102][102];
bool f[102][102];
short int len[102][102];
short int lans=-1;
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
    cin>>r>>c;
    for(short int i=1;i<=r;i++){
        for(short int j=1;j<=c;j++){
            cin>>a[i][j];
        }
    }
    for(short int i=1;i<=r;i++){
        for(short int j=1;j<=c;j++){
            queue<sb>q;
            sb temp;
            temp.x=i;
            temp.y=j;
            q.push(temp);
            len[i][j]=1;
            while(!q.empty()){
				sb rr=q.front();
				q.pop();
				for(short int t=0;t<4;t++){
					sb x1;
					x1.x=rr.x+fl[t][0];
					x1.y=rr.y+fl[t][1];
					if(a[x1.x][x1.y]<a[rr.x][rr.y]&&(x1.x>=1&&x1.x<=r)&&(x1.y>=1&&x1.y<=c)&&f[x1.x][x1.y]==false){
						f[x1.x][x1.y]==true;
						q.push(x1);
						len[x1.x][x1.y]=len[rr.x][rr.y]+1;
					}
				}
            }
            short int ans=-1;
            for(short int k=1;k<=r;k++){
            	for(short int y=1;y<=c;y++){
            		ans=max(ans,len[k][y]);
				}
			}
			lans=max(lans,ans);	
        }
    }
    cout<<lans;
    return 0;
}