public static void main(String[] args) {

    Scanner input = new Scanner(System.in);

    int n = 0;

    System.out.println("Enter number n:");
    n = input.nextInt();

    char[][] ls = new char[n][n];
    String tempString = "";

    for(int i = 0 ; i < n ; i++)
    {
        for(int j = 0 ; j < n ; j++)
        {
            System.out.println("Enter the letter for " + i + "," + j);
            tempString = input.nextLine();
            if(tempString.length() > 1)
            {
                System.out.println("Invalid input");
            }
            else
            {
                ls[i][j] = tempString.charAt(0);
            }
        }
    }

    boolean latinSquare = true;
    for(int i = 0 ; i < n && latinSquare ; i++)
    {
        for(int j = 0 ; j < n && latinSquare ; j++)
        {
            char element = ls[i][j];
            for(int k = j + 1 ; k < n && latinSquare ; k++)
            {
                if(ls[i][j] == element)
                {
                    latinSquare = false;
                }
            }
            for(int k = i + 1 ; k < n && latinSquare ; k++)
            {
                if(ls[i][j] == element)
                {
                    latinSquare = false;
                }
            }
        }
    }
    if(latinSquare)
    {
        System.out.println("The square is a latin square");
    }
    else
    {
        System.out.println("The square is not a latin square");
    }
}