#include <iostream>
#include <cstring>

using namespace std;

int main()
{
	int n, m;
	cin >> n >> m;

	int a[n+2][m+2];
	memset(a, 0, sizeof(a));
	for (int i = 1; i < n+1; i++)
		for (int j = 1; j < m+1; j++)
			cin >> a[i][j];

	int x = 1, y = 1, flag = 0;
	for (int i = 0; i < n*m; i++)
	{
		cout << a[x][y] << " ";
		a[x][y] = 0;
		if (flag == 0)
		{
			if (a[x][y+1] != 0) y++;
			else {	flag = 1; x++; }
			continue;
		}
		if (flag == 1)
		{
			if (a[x+1][y] != 0) x++;
			else {	flag = 2; y--; }
			continue;
		}
		if (flag == 2)
		{
			if (a[x][y-1] != 0) y--;
			else {	flag = 3; x--; }
			continue;
		}
		if (flag == 3)
		{
			if (a[x-1][y] != 0) x--;
			else {	flag = 0; y++; }
			continue;
		}
	}

	return 0;
}