#include<iostream>
using namespace std;
int r,c,a[100][100],s[100][100];
int b[100][100];
int pos[4][2] = {{1,0},{-1,0},{0,1},{0,-1}};
bool check(int xnow,int ynow,int tox,int toy){
    if(tox>=0&&tox<=r&&toy>=0&&toy<=c&&b[tox][toy]==0&&a[tox][toy]<a[xnow][ynow]) return true;
    return false;
}
int dfs(int x,int y){
    if(s[x][y]) return s[x][y];
    s[x][y] = 1;
    for(int q = 0;q<4;q++){
        int xnext = x+pos[q][0];
        int ynext = y+pos[q][1];
        if(check(x,y,xnext,ynext)){
            b[xnext][ynext] = 1;
            dfs(xnext,ynext);
            b[xnext][ynext] = 0;
            s[x][y] = max(s[x][y],s[xnext][ynext]+1);
        }
    }
    return s[x][y];
}
int main(){
    cin>>r>>c;
    for(int i = 0;i<r;i++){
        for(int j = 0;j<c;j++){
            cin>>a[i][j];
        }
    }
    for(int i = 0;i<r;i++){
        for(int j = 0;j<c;j++){
            b[i][j] = 1;
            dfs(i,j);
            b[i][j] = 0;
        }
    }
    int maxn = 1;
    for(int i = 0;i<r;i++){
        for(int j = 0;j<c;j++){
            if(s[i][j] > maxn){
                maxn = s[i][j];
            }
        }
    }
    cout<<maxn;
    return 0;
}