#define _USE_MATH_DEFINES
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <math.h>
#include <cmath>
#include <stack>
#include <map>
#include <set>
#include <numeric>
#include <iomanip>
#include <climits>
#include <functional>
#include <cassert>
#include <tuple>
using namespace std;
using ll = long long;

int H, W;
int A[505][505], vis[505][505];
int dx[4] = {1,0,-1,0};
int dy[4] = {0,1,0,-1};

void dfs(int y, int x) {

    int mx = 0;
    for(int i = 0; i < 4; ++i) {
        int nx = x+dx[i];
        int ny = y+dy[i];
        if(nx < 0 || nx >= W || ny < 0 || ny >= H) continue;
        if(A[y][x] >= A[ny][nx]) continue;
        if(vis[ny][nx] == 0) dfs(ny, nx);
        mx = max(mx, vis[ny][nx]);
    }

    vis[y][x] = mx+1;

}

int main() {

    cin >> H >> W;
    for(int i = 0; i < H; ++i) {
        for(int j = 0; j < W; ++j) {
            cin >> A[i][j];
        }
    } 

    int ans = 0;
    for(int i = 0; i < H; ++i) {
        for(int j = 0; j < W; ++j) {
            if(vis[i][j] != 0) {
                ans = max(ans, vis[i][j]);
                continue;
            }
            dfs(i,j);
            ans = max(ans,vis[i][j]);
        }
    }

    cout << ans << endl;

}