diff --git a/mark/day7/example.txt b/mark/day7/example.txt
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diff --git a/mark/day7/input.txt b/mark/day7/input.txt
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diff --git a/mark/day7/part1.rb b/mark/day7/part1.rb
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+++ b/mark/day7/part1.rb
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+require 'debug'
+
+# Generic FileHandler
+class FileHandler
+  def initialize(file_path)
+    @file_path = file_path
+  end
+
+  # Usage:
+  # FileHandler.new('/path_to_file').read_lines do |line|
+  #   # process line
+  # end
+  def read_lines
+    File.foreach(@file_path, chomp: true).map do |line|
+      yield(line)
+    end
+  end
+
+  # Usage:
+  # file_content = FileHandler.new('/path_to_file').read_file(
+  def read_file
+    File.read(@file_path)
+  end
+end
+
+class PuzzleSolver
+  def initialize(file_handler, debug: false)
+    @handler = file_handler
+    @debug = debug
+  end
+
+  def debug(message)
+    puts message if @debug
+  end
+
+  def print_debug(message)
+    print message if @debug
+  end
+
+  def solve
+    raise NotImplementedError, 'Please implement this method in subclasses.'
+  end
+end
+
+# TODO: Puzzle-specific
+
+
+
+if ARGV[0].nil? || ARGV[0].empty?
+  puts "Usage: ruby #{__FILE__} <file_name> [debug]"
+  exit 1
+end
+file_path = ARGV[0]
+debug = (ARGV[1] == "debug")
+file_handler = FileHandler.new(file_path)
+
+## Puzzle-specific
+cls = PuzzleSolver
+##
+
+puts "The answer is: #{cls.new(file_handler, debug:).solve}"