class Program {
    static void Main() {
        // get all the words form the text file and put them into a hasset
        var words = new List<string>(File.ReadAllLines("input.txt"));
        var wordSet = new HashSet<string>(words);

        // Find all combos that forn a 6 letter word and make sure we dont have duplicates
        var seenCombinations = new HashSet<string>();
        var combos = words.SelectMany(
                word1 => words.Where(word2 => word1 != word2),
                (word1, word2) => new { word1, word2, combinedWord = word1 + word2 }
        ).Where(
            x => x.combinedWord.Length == 6 && wordSet.Contains(x.combinedWord)
        ).Where(
            x => seenCombinations.Add($"{x.word1}+{x.word2}")
        ).Select(
            x => $"{x.word1}+{x.word2}={x.combinedWord}"
        ).ToList();

        // echo out all found words
        combos.ForEach(Console.WriteLine);

    }
}