Lego Blocks

package com.company;

import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        boolean equal = true;
        int rows = Integer.parseInt(input.nextLine());
        String[][] firstArray = new String[rows][];
        String[][] secondArray = new String[rows][];
        int totalLength = 0;
        for (int i = 0; i < rows; i++) {
            firstArray[i] = input.nextLine().trim().split("\\s+");
            totalLength += firstArray[i].length;
        }
        for (int j = 0; j < rows; j++) {
            secondArray[j] = input.nextLine().trim().split("\\s+");
            totalLength += secondArray[j].length;
        }
        int template = firstArray[0].length + secondArray[0].length;
        for (int k = 0; k < rows; k++) {
            if (firstArray[k].length + secondArray[k].length != template) {
                equal = false;
            }
        }
        if (equal == false) {
            System.out.println("The total number of cells is: " + totalLength);
        }
        else {
            for (int m = 0; m < rows; m++) {
                System.out.print("[");
                System.out.print(combine(firstArray[m], ", "));
                System.out.print(", ");
                Collections.reverse(Arrays.asList(secondArray[m]));
                System.out.print(combine(secondArray[m], ", "));
                System.out.println("]");
            }
        }
    }
    public static String combine(String[] s, String glue)
    {
        int k = s.length;
        if ( k == 0 )
        {
            return null;
        }
        StringBuilder out = new StringBuilder();
        out.append( s[0] );
        for ( int x=1; x < k; ++x )
        {
            out.append(glue).append(s[x]);
        }
        return out.toString();
    }
}