#include <iostream>

using namespace std;

int a[1005][1005], n, m;

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

    for(int i = 1; i <= n; ++i)
        for(int j = 1; j <= m; ++j)
            cin >> a[i][j];

    int d = 1, x = 1, y = 1;
    while(d != -1)
    {
        if(a[x][y] != 0)
            cout << a[x][y] << ' ';
        a[x][y] = 0;
        switch(d)
        {
            case(1):{
                if(a[x][y+1] == 0)
                {
                    if(a[x+1][y] == 0)
                        d = -1;
                    else
                        d = 2;
                }
                else
                    ++y;
                break;
            }
            case(2):{
                if(a[x+1][y] == 0)
                    d = 3;
                else
                    ++x;
                break;
            }
            case(3):{
                if(a[x][y-1] == 0)
                    d = 4;
                else
                    --y;
                break;
            }
            case(4):{
                if(a[x-1][y] == 0)
                    d = 1;
                else
                    --x;
                break;
            }
        }
    }
    return 0;
}