import java.util.*;
public class Main {
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
int n=sc.nextInt();
int m=sc.nextInt();
int [][]arr=new int[n][m];
for(int i=0;i<arr.length;i++) {
for(int j=0;j<arr[i].length;j++) {
arr[i][j]=sc.nextInt();
}
}
printrowwise(arr);
sc.close();
} public static void printrowwise(int [][]arr) {
for(int i=0;i<arr.length;i++) {
if(i%2==0) {
for(int j=0;j<arr[i].length;j++) {
System.out.print(arr[i][j]+",");
}
} else {
for(int j=arr[i].length-1;j>=0;jā) {
System.out.print(arr[i][j]+",");
}
}
}
System.out.println("END ");
}
}
