теперь вот так

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Word = Microsoft.Office.Interop.Word;
using Excel = Microsoft.Office.Interop.Excel;
using System.Reflection;

namespace SYATP1
{


    class Program
    {
        static string[,] dataFromTheTable;
        static Dictionary<string, string> groupsAndPhrases;
        static HashSet<string> countingTriads;
        static int numberOfPhrases;
        static int numberOfNames;
        static int numberOfGroups;
        static HashSet<string> groups1;
        static HashSet<string> groups2;
        static List<string> names;
        static List<ValueTuple<string, int>> phrases;
        static int[] rangesByGroups;
        static int k = 0;
        static int randomName;
         static int randomGroup ;
        static int randomPhrases;
        static object MissingObject = Missing.Value;
        static Word.Application wordApp;
        static string wish;
        static string triads;
        static List<int> triads_;


        static string wordDocTemplate = @"C:\Users\margo\source\repos\SYATP1\Поздравления.docx";
        static Word.Document document = null;

        static void Readingdata()
        {
            Excel.Application excelApp = new Excel.Application();
            //excelApp.Visible = true;
            string file_path = @"C:\Users\margo\source\repos\SYATP1\Входные_данные.xlsx";
            Excel.Workbook wb = excelApp.Workbooks.Open(file_path);
            Excel.Worksheet ws1 = wb.Worksheets["Имена"];
            Excel.Worksheet ws2 = wb.Worksheets["Группы и пожелания"];
            Excel.Worksheet ws3 = wb.Worksheets["Настройки"];
            numberOfPhrases = ws2.Rows.CurrentRegion.EntireRow.Count;
            numberOfNames = ws1.Rows.CurrentRegion.EntireRow.Count;
            dataFromTheTable = new string [numberOfPhrases,2];
            for (int j = 0; j < 2; j++)
                for (int i = 0; i < numberOfPhrases; i++)
                    dataFromTheTable[i, j] = ws2.Cells[i + 1, j + 1].Text.ToString();
            phrases = new List<ValueTuple<string, int>>();

             for (int j = 0; j < 2; j++)
                for (int i = 0; i < numberOfPhrases; i++)
                 Console.WriteLine (dataFromTheTable[i, j]);
            groupsAndPhrases = new Dictionary<string, string>();
            for (int i = 0; i < numberOfPhrases; i++)
            {
                groupsAndPhrases.Add(dataFromTheTable[i, 1], dataFromTheTable[i, 0]);
            }

            groupsAndPhrases = groupsAndPhrases.OrderBy(pair => pair.Value).ToDictionary(pair => pair.Key, pair => pair.Value);

            foreach (var item in groupsAndPhrases)
            {
                (string, int) tuple = (item.Key, 0);
                phrases.Add(tuple);
            }
            groups1 = new HashSet<string>();
            groups2 = new HashSet<string>();
            foreach (var item in groupsAndPhrases)
                groups1.Add( item.Value);
             numberOfGroups = groups1.Count;
               Console.WriteLine(numberOfGroups);
            rangesByGroups = new int[numberOfGroups + 1];
            for (int i = 0; i < numberOfGroups + 1; i++)
            {
                rangesByGroups[i] = 1;

            }


            foreach (var item in groupsAndPhrases)
            {   if (!groups2.Add(item.Value))

                    rangesByGroups[k]++;


                else

                     k++;


            }

            for (int i = 1; i < numberOfGroups; i++)
            {

                rangesByGroups[i + 1] += rangesByGroups[i];

            }




                for (int i = 1; i < numberOfGroups+1; i++)

                Console.WriteLine(rangesByGroups[i]);


            names = new List<string>();
            for (int i = 0; i < numberOfNames; i++)
                names.Add( ws1.Cells[i+1, 1].Text.ToString());
            foreach (var item in names)
            {
                Console.WriteLine(item);
            }
            excelApp.Quit();
        }
        static bool proverka()
        {   triads_.Sort();
            for (int i = 0; i < 3; i++)
            {
                triads += triads_[i].ToString();
            }

            Console.WriteLine(triads);
            return (countingTriads.Add(triads));

        }
        static void Random()
        {
            triads_.Clear();
            triads = "";
            wish = "";
            Random rnd = new Random();
             randomName = rnd.Next(1, numberOfNames + 1);

            do
            {
                for (int j = 0; j < 3; j++)
                {


                    randomGroup = rnd.Next(1, numberOfGroups + 1);
                    ValueTuple<string, int> [] l = new ValueTuple<string, int>[rangesByGroups[randomGroup] - rangesByGroups[randomGroup - 1]];
                    phrases.CopyTo(rangesByGroups[randomGroup - 1], l, 0, rangesByGroups[randomGroup] - rangesByGroups[randomGroup - 1]);

                    int rndom = l.Min(x => x.Item2);


                    int minimumValueIndex = Array.FindIndex(l,x => x.Item2==rndom);
                    int index = phrases.IndexOf(l[minimumValueIndex]);
                    randomPhrases = index;

                        triads_.Add(index);
                        wish = wish + phrases[index].Item1 + ", ";
                    int n2 = phrases[index].Item2;
                    n2++;
                    string n1 = phrases[index].Item1;
                    (string, int) n = (n1, n2);
                    phrases[index] = n;
                }
            } while (!proverka());






            }
        static void writingToTheWord()
        {
            //object MissingObject = Missing.Value;
            /*Word.Application*/ //wordApp = new Word.Application();
            //wordApp.Visible = true;
            //string wordDocTemplate = @"C:\Users\margo\source\repos\SYATP1\Поздравления.docx";
            //Word.Document document = null;
            try
            {
                //document = wordApp.Documents.Add(wordDocTemplate);
                document.Bookmarks["name"].Range.Text = names[randomName-1];
                string wishNoGaps  = wish.Substring(0, wish.Length - 2);

                document.Bookmarks["wish"].Range.Text = wishNoGaps;
                var endOfFile = document.Bookmarks["\\endofdoc"].Range;
                endOfFile.InsertBreak(Word.WdBreakType.wdPageBreak);
                endOfFile.InsertFile(@"C:\Users\margo\source\repos\SYATP1\Поздравления.docx");
            }
            catch (Exception e)
            {
                document.Close(Word.WdSaveOptions.wdDoNotSaveChanges);
                wordApp.Quit();
                document = null;
                wordApp = null;
                Console.WriteLine(e.Message);
            }


        }

        static void Main(string[] args)
        {

            Readingdata();
            wordApp = new Word.Application();
            wordApp.Visible = true;
            document = wordApp.Documents.Add(wordDocTemplate);
            countingTriads = new HashSet<string>();
            triads_ = new List<int>();
            for (int i = 0; i < 100; i++)
            {
                Random();
                writingToTheWord();
            }

            wordApp.Quit();
        }
    }
}