#include<iostream>
#include<cstring>
#include<algorithm>

using namespace std;

const int N = 310;
int h[N][N];    //山高；
int f[N][N];
int dx[4] = {-1, 1, 0, 0}; // 方向数组
int dy[4] = {0, 0, -1, 1};
int n, m;
int dfs (int x, int y)
{
    if (f[x][y] != -1) return f[x][y];
    
    f[x][y] = 1;
    for (int i=0; i < 4; i ++)
    {
        int a = x + dx[i], b = y + dy[i];
        if (a>=1 && a<=n && b>=1 && b<=m && h[x][y]>h[a][b])
            f[x][y] = max(f[x][y], dfs(a, b) + 1);
    }
    return f[x][y];
}

int main()
{
    cin >> n >> m;
    
    for (int i=1; i <= n;  i++)
        for (int j=1; j <= m; j ++)
            cin >> h[i][j];
        
    memset (f, -1, sizeof(f));
    int res=0;
    for (int i=1; i <= n; i ++)
        for (int j=1; j <= m; j ++)
            res = max(res, dfs(i, j));
    cout << res;
    return 0;
}