import os

def get_file_with_most_lines(directory):
    max_lines = 0
    target_file = ""

    for filename in os.listdir(directory):
        filepath = os.path.join(directory, filename)
        if os.path.isfile(filepath):
            with open(filepath, 'r') as f:
                line_count = sum(1 for _ in f)
                if line_count > max_lines:
                    max_lines = line_count
                    target_file = filename

    return target_file

def copy_file(src_directory, dest_directory, filename):
    src_filepath = os.path.join(src_directory, filename)
    dest_filepath = os.path.join(dest_directory, 'data.txt')

    os.makedirs(dest_directory, exist_ok=True)

    with open(src_filepath, 'r') as src_file:
        with open(dest_filepath, 'w') as dest_file:
            dest_file.write(src_file.read())

def main():
    src_directory = '/var/data'
    dest_directory = '/var/result'

    target_file = get_file_with_most_lines(src_directory)
    if target_file:
        copy_file(src_directory, dest_directory, target_file)
        print(f"File {target_file} copied to {dest_directory}/data.txt")

if __name__ == "__main__":
    main()