#include <iostream>
#include<queue>
#include<cmath>
using namespace std;

int n, m, map[105][105] = { 0 };//行，列，地图

int k[105][105] = { 0 }, ans = 0;

int fx[4] = { 1,-1,0,0 }, fy[4] = { 0,0,1,-1 };//方向

int dfs(int x, int y) 
{
    if (k[x][y])return k[x][y];
    k[x][y] = 1;
    int xl, yl;
    for (int i = 0; i < 4; i++)
    {
        xl = fx[i] + x;
        yl = fy[i] + y;
        if (xl<1 || xl>n || yl<1 || yl>m || map[xl][yl] > map[x][y])continue;
        dfs(xl, yl);
        k[x][y] = max(k[x][y], k[xl][yl] + 1);
    }
    return k[x][y];
}

int main()
{
    //输入
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            cin >> map[i][j];
        }
    }

    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            ans = max(ans, dfs(i, j));
        }
    }
    cout << ans << endl;
    return 0;
}