using System;
using System.IO;

class Program
{
    static void Main()
    {
        const string inputDir = "/var/data";
        const string outputFile = "/var/result/data.txt";

        try
        {
            using (var writer = new StreamWriter(outputFile))
            {
                var files = Directory.GetFiles(inputDir);
                foreach (var file in files)
                {
                    using (var reader = new StreamReader(file))
                    {
                        string firstLine = reader.ReadLine();
                        if (!string.IsNullOrEmpty(firstLine))
                        {
                            writer.WriteLine(firstLine);
                        }
                    }
                }
            }

            Console.WriteLine($"Файл {outputFile} успешно создан.");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Ошибка: {ex.Message}");
        }
    }
}