code by NightmareZ

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace App
{
    class Program
    {
        static IEnumerable<string> ToLines(IEnumerable<object> list, int spaces = 0)
        {
            foreach (object obj in list)
            {
                string pre = string.Join(string.Empty, Enumerable.Repeat(" ", spaces));

                if (obj is int)
                    yield return pre + obj;
                else
                {
                    var kvp = (KeyValuePair<int, List<object>>)obj;
                    yield return string.Format("{0}repeat {1}:", pre, kvp.Key);
                    foreach (string line in ToLines(kvp.Value, spaces + 4))
                        yield return line;
                }
            }
        }

        static bool Compare(object obj1, object obj2)
        {
            if (obj1 is int && !(obj2 is int)) return false;
            if (obj2 is int && !(obj1 is int)) return false;

            if (obj1 is int && obj2 is int)
                return (int) obj1 == (int) obj2;

            var kvp1 = (KeyValuePair<int, List<object>>)obj1;
            var kvp2 = (KeyValuePair<int, List<object>>)obj2;

            if (kvp1.Key != kvp2.Key) return false;
            if (kvp1.Value.Count != kvp2.Value.Count) return false;

            return !kvp1.Value.Where((t, i) => !Compare(t, kvp2.Value[i])).Any();
        }

        static IEnumerable<object> Process(IEnumerable<object> source, int depth)
        {
            var list = new List<object>(source);
            var result = new List<object>(list.Count);
            bool sublistsCreated = false;

            for (int startIdx = 0; startIdx < list.Count; ++startIdx)
            {
                var counts = Enumerable.Repeat(0, depth).ToList();

                for (int rangeLen = 1;
                     rangeLen <= depth && startIdx + rangeLen <= list.Count;
                     ++rangeLen)
                {
                    int count = 0;
                    bool eq;

                    do
                    {
                        ++count;
                        eq = true;

                        for (int i = 0; i < rangeLen; ++i)
                        {
                            int idx0 = startIdx + i;
                            int idx1 = startIdx + rangeLen*count + i;

                            if (idx1 >= list.Count)
                            {
                                eq = false;
                                break;
                            }

                            if (!Compare(list[idx0], list[idx1]))
                            {
                                eq = false;
                                break;
                            }
                        }
                    } while (eq);

                    counts[rangeLen - 1] = count;
                }

                int max = counts.Max();
                int maxDepth = counts.IndexOf(max) + 1;

                if (max == 1)
                    result.Add(list[startIdx]);
                else
                {
                    var subList = new List<object>(maxDepth);

                    for (int i = 0; i < maxDepth; ++i)
                        subList.Add(list[startIdx + i]);

                    subList = Process(subList, depth).ToList();
                    result.Add(new KeyValuePair<int, List<object>>(max, subList));
                    sublistsCreated = true;
                    startIdx += maxDepth * max - 1;
                }
            }

            if (sublistsCreated)
                result = Process(result, depth).ToList();

            return result;
        }

        static void Main()
        {
            const string inputFileName = @"input.txt";
            const string outputFileName = @"output.txt";

            var source = (from line in File.ReadAllLines(inputFileName)
                          select (object)int.Parse(line.Trim())).ToList();

            var result = Process(source, source.Count);
            File.WriteAllLines(outputFileName, ToLines(result));

            foreach (var line in ToLines(result))
                Console.WriteLine(line);
            Console.ReadKey();
        }
    }
}