#include <iostream>
#include <cstring>
using namespace std;
const int N = 310;
int f[N][N], g[N][N];
int n, m;
int dp(int x, int y) {
if (f[x][y] != -1) return f[x][y];
f[x][y] = 1;
int dx[] = {-1, 0, 1, 0}, dy[] = {0, 1, 0, -1};
for (int i = 0; i < 4; i++) {
int a = x + dx[i], b = y + dy[i];
if (a < 0 || a >= n || b < 0 || b >= m) continue;
if (g[a][b] < g[x][y]) f[x][y] = max(f[x][y], dp(a, b) + 1);
}
return f[x][y];
}
int main() {
cin >> n >> m;
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
cin >> g[i][j];
memset(f, -1, sizeof f);
int res = 0;
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
res = max(res, dp(i, j));
cout << res << endl;
return 0;
}