//Dragan Andrei Gabriel
//University of Bucharest

#include <cstdio>
#include <cassert>
#include <cmath>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <istream>
#include <ostream>
#include <deque>
#include <map>
#include <queue>
#include <stack>
#include <set>
#include <vector>
#include <algorithm>
#include <functional>
#include <string>
#include <utility>
using namespace std;

int n, m, x, y, v[1001][1001];

int main()
{
    #ifndef ONLINE_JUDGE
    freopen("a.in", "r", stdin);
    freopen("a.out", "w", stdout);
    #endif

    scanf("%d %d", &n, &m);
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            scanf("%d", &v[i][j]);
    x = y = 1;
    while (x <= n || y <= n)
    {
        for (int j = 1; j <= m; j++)
            if (v[x][j])
                printf("%d ", v[x][j]), v[x][j] = 0;
        for (int i = 1; i <= n; i++)
            if (v[i][m - y + 1])
                printf("%d ", v[i][m - y + 1]), v[i][m - y + 1] = 0;
        for (int j = m; j >= 1; j--)
            if (v[n - x + 1][j])
                printf("%d ", v[n - x + 1][j]), v[n - x + 1][j] = 0;
        for (int i = n; i >= 1; i--)
            if (v[i][y])
                printf("%d ", v[i][y]), v[i][y] = 0;
        x++;
        y++;
    }
    return 0;
}