import javax.swing.*;
public class recorrido {
public static void main (String [] args) {
int i,j,k,n,m,s;
int a[][] = new int [10][10];
int v[] = new int [100];
String st;
n=Integer.parseInt(JOptionPane.showInputDialog("n° filas"));
m=Integer.parseInt(JOptionPane.showInputDialog("n° columnas"));
for (i=1;i<=n;i++){
for(j=1;j<=m;j++){
a[i][j]=Integer.parseInt(JOptionPane.showInputDialog("a[ "+i+j+ " ]="));
}
}
if(n % 2==0){
k=0;
for(i=n;i<=1;i--){ // ********** "<=" cambiar ">="
if(i % 2==0){
for(j=m;j<=1;j--){ // ********** "<=" cambiar ">="
k++;
v[k]=a[i][j];
}
}else{
for (j=1;j<=m;j++){
k++;
v[k]=a[i][j];
}
}
}
}else{
k=0;
for(i=n;i<=1;i--){ // ********** "<=" cambiar ">="
if(i % 2!=0){
for(j=m;j<=1;j--){ // ********** "<=" cambiar ">="
k++;
v[k]=a[i][j];
}
}else{
for(j=1;j<=m;j++){
k++;
v[k]=a[i][j];
}
}
}
}
st=" ";
for (s=1;s<=k;s++){
st= st + v[s] + " ";
}
JOptionPane.showMessageDialog(null, st );
}
}