---

static (bool, int) find(string source, string word)
        {
            for (int i = 0; i < source.Length - word.Length+1; i++)
            {
                if (source[i] == word[0])
                {
                    for (int k = 0; k < word.Length; k++)
                    {
                        if (source[i + k] != word[k]) break;
                        if (k == word.Length-1 && source[i + k] == word[k]) return (true, i);
                    }  
                }
            }
            return (false, -1);
        }