Problem:
Problem C: Emacs-like Editor

Emacs is a text editor which is widely used by many programmers.

The advantage of Emacs is that we can move a cursor without arrow keys and the mice. For example, the cursor can be moved right, left, down, and up by pushing f, b, n, p with the Control Key respectively. In addition, cut-and-paste can be performed without the mouse.

Your task is to write a program which simulates key operations in the Emacs-like editor. The program should read a text and print the corresponding edited text.

The text consists of several lines and each line consists of zero or more alphabets and space characters. A line, which does not have any character, is a blank line.

The editor has a cursor which can point out a character or the end-of-line in the corresponding line. The cursor can also point out the end-of-line in a blank line.

In addition, the editor has a buffer which can hold either a string (a sequence of characters) or a linefeed.

The editor accepts the following set of commands (If the corresponding line is a blank line, the word "the first character" should be "the end-of-line"):

a

Move the cursor to the first character of the current line.

e

Move the cursor to the end-of-line of the current line.

p

Move the cursor to the first character of the next upper line, if it exists.

If there is no line above the current line, move the cursor to the first character of the current line.

n

Move the cursor to the first character of the next lower line, if it exists.

If there is no line below the current line, move the cursor to the first character of the current line.

f

Move the cursor by one character to the right, unless the cursor points out the end-of-line.

If the cursor points out the end-of-line and there is a line below the current line, move the cursor to the first character of the next lower line. Otherwise, do nothing.

b

Move the cursor by one character to the left, unless the cursor points out the first character.

If the cursor points out the first character and there is a line above the current line, move the cursor to the end-of-line of the next upper line. Otherwise, do nothing.

d

If the cursor points out a character, delete the character (Characters and end-of-line next to the deleted character are shifted to the left).

If the cursor points out the end-of-line and there is a line below, the next lower line is appended to the end-of-line of the current line (Lines below the current line are shifted to the upper).
Otherwise, do nothing.

k

If the cursor points out the end-of-line and there is a line below the current line, perform the command d mentioned above, and record a linefeed on the buffer.

If the cursor does not point out the end-of-line, cut characters between the cursor (inclusive) and the end-of-line, and record them on the buffer. After this operation, the cursor indicates the end-of-line of the current line.

y

If the buffer is empty, do nothing.

If the buffer is holding a linefeed, insert the linefeed at the cursor. The cursor moves to the first character of the new line.

If the buffer is holding characters, insert the characters at the cursor. The cursor moves to the character or end-of-line which is originally pointed by the cursor.

The cursor position just after reading the text is the beginning of the first line, and the initial buffer is empty.

Input

The input consists of only one data-set which includes two parts. The first part gives a text consisting of several lines. The end of the text is indicated by a line (without quotes):

"END_OF_TEXT"

This line should not be included in the text.

Next part gives a series of commands. Each command is given in a line. The end of the commands is indicated by a character '-'.

Output

For the input text, print the text edited by the commands.

Constraints

The number of lines in the text given as input ≤ 10

The number of characters in a line given as input ≤ 20

The number of commands ≤ 300

The maximum possible number of lines in the text during operations ≤ 100

The maximum possible number of characters in a line during operations ≤ 1000

Sample Input

hyo
ni
END_OF_TEXT
f
d
f
f
k
p
p
e
y
a
k
y
y
n
y
-

Output for the Sample Input

honihoni
honi

Solution in Ruby (judge verdict: Accepted)

X = 1
Y = 0

class Editor
  def initialize
    @text = []
    @buffer = ''
    @cursor = [0, 0]
  end

  def line_start?
    @cursor[Y] == 0
  end

  def line_end?
    @cursor[Y] == @text.size - 1
  end

  def str_start?
    @cursor[X] == 0
  end

  def str_end?
    y = @cursor[Y]
    @cursor[X] == @text[y].size
  end

  def character?
    (not str_end?)
  end

  attr_accessor :text, :buffer, :cursor
end

class CommandA
  def self.execute editor
    editor.cursor[X] = 0
  end
end

class CommandE
  def self.execute editor
    y = editor.cursor[Y]
    editor.cursor[X] = editor.text[y].size
  end
end

class CommandP
  def self.execute editor
    editor.cursor[Y] -= 1 unless editor.line_start?
    editor.cursor[X] = 0
  end
end

class CommandN
  def self.execute editor
    editor.cursor[Y] += 1 unless editor.line_end?
    editor.cursor[X] = 0
  end
end

class CommandF
  def self.execute editor
    y = editor.cursor[Y]
    if not editor.str_end?
      editor.cursor[X] += 1
    elsif not editor.line_end?
      editor.cursor[Y] += 1
      editor.cursor[X] = 0
    end
  end
end

class CommandB
  def self.execute editor
    if not editor.str_start?
      editor.cursor[X] -= 1
    elsif not editor.line_start?
      editor.cursor[Y] -= 1
      y = editor.cursor[Y]
      editor.cursor[X] = editor.text[y].size
    end
  end
end

class CommandD
  def self.execute editor
    x = editor.cursor[X]
    y = editor.cursor[Y]

    if editor.character?
      editor.text[y].slice!(x)
    elsif editor.str_end? and not editor.line_end?
      editor.text[y] << editor.text[y+1]
      editor.text.slice!(y+1)
    end
  end
end

class CommandK
  def self.execute editor
    x = editor.cursor[X]
    y = editor.cursor[Y]

    if editor.character?
      editor.buffer = editor.text[y].slice!(x..-1)
    elsif editor.str_end? and not editor.line_end?
      editor.buffer = '\n'
      editor.text[y] << editor.text[y+1]
      editor.text.slice!(y+1)
    end
  end
end

class CommandY
  def self.execute editor
    unless editor.buffer.empty?
      x = editor.cursor[X]
      y = editor.cursor[Y]

      if editor.buffer == '\n'
        str = editor.text[y].slice!(x..-1)
        editor.text.insert(y+1, str)
        editor.cursor[X] = 0
        editor.cursor[Y] += 1
      else
        editor.text[y].insert(x, editor.buffer)
        editor.cursor[X] += editor.buffer.size
      end
    end
  end
end

def main
  editor = Editor.new
  loop do
    line = gets.chomp
    break if line == 'END_OF_TEXT'
    editor.text << line
  end

  command_list = []
  loop do
    command = gets.chomp
    break if command == '-'
    command_list << command
  end

  command_list.each do |command|
    eval("Command#{command.upcase}").execute(editor)
  end

  editor.text.each {|line| puts line}
end

main