import java.util.Scanner;

public class Main {

	public static void main(String[] arg) {
		Scanner cin = new Scanner(System.in);
		int row = cin.nextInt();
		int col = cin.nextInt();
		double[][] hight = new double[row + 2][col + 2];
		int[][] lian = new int[row + 2][col + 2];

		for (int j = 0; j < col + 2; j++) {
			lian[0][j] = lian[row + 1][j] = 0;
			hight[0][j] = hight[row + 1][j] = 1050;
		}
		for (int i = 0; i < row + 2; i++) {
			lian[i][0] = lian[i][col + 1] = 0;
			hight[i][0] = hight[i][col + 1] = 1050;
		}
		for (int i = 1; i < row + 1; i++) {
			for (int j = 1; j < col + 1; j++) {
				hight[i][j] = cin.nextDouble();
				lian[i][j] = 0;
			}
		}

		int zui = 0;
		for (int i = 1; i < row + 1; i++) {
			for (int j = 1; j < col + 1; j++) {
				int temp = piao(hight, lian, i, j);

				if (zui < temp)
					zui = temp;

			}

		}
		System.out.println(zui);

	}

	public static int piao(double[][] h, int[][] lian, int i, int j) {

		if (lian[i][j] == 0) {
			int temp1 = 1, temp2 = 1, temp3 = 1, temp4 = 1;
			if (h[i][j] > h[i][j + 1]) {
				if (lian[i][j + 1] != 0)
					temp1 = lian[i][j + 1] + 1;
				else
					temp1 = piao(h, lian, i, j + 1) + 1;
			}
			if (h[i][j] > h[i - 1][j]) {
				if (lian[i - 1][j] != 0)
					temp2 = lian[i - 1][j] + 1;
				else
					temp2 = piao(h, lian, i - 1, j) + 1;
			}
			if (h[i][j] > h[i][j - 1]) {
				if (lian[i][j - 1] != 0)
					temp3 = lian[i][j - 1] + 1;
				else
					temp3 = piao(h, lian, i, j - 1) + 1;
			}
			if (h[i][j] > h[i + 1][j]) {
				if (lian[i + 1][j] != 0)
					temp4 = lian[i + 1][j] + 1;
				else
					temp4 = piao(h, lian, i + 1, j) + 1;
			}
			if (temp2 > temp1)
				temp1 = temp2;
			if (temp4 > temp3)
				temp3 = temp4;
			if (temp1 < temp3)
				temp1 = temp3;

			lian[i][j] = temp1;
		}
		return lian[i][j];

	}
}