ShellBound - Nested dict

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
/*  Vladi is a crab. Crabs are scared from almost anything, which is why they usually hide in their shells. Vladi is a rich crab //though.
        //He has acquired many outer shells, in different regions, in which he can hide – each with a different size.
        //However, it is really annoying to look after all your shells when they are so spread. That is why, Vladi decided to merge all //shells
        //in each region, so that he has one big shell for every region. He needs your help to do that.
        //You will be given several input lines containing a string and an integer, separated by a space. The string will represent the //region’s
        //name, and the integer – the shell, in the given region, size.
        //You must store all shells in their corresponding regions.
        //If the region already exists, add the new shell to it. Make sure you have NO duplicate shells (shells with same size). Vladi //doesn’t like shells with the same size.
        //When you receive the command “Aggregate”, you must stop reading input lines, and you must print every region, all of the //shells in that
        //region, and the size of the giant shell after you’ve merged them in the following format:
        //{regionName} -> {shell1, shell2, shell3…} ({giantShell})
        //The giant shell size is calculated when you subtract the average of the shells from the sum of the shells.
        //Or in other words: (sum of shells) – (sum of shells) / (count of shells). */
namespace ShellBound
{
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary<string, List<int>> register = new Dictionary<string, List<int>>();
            string inputline = Console.ReadLine();
            while (inputline != "Aggregate")
            {
                var inputData = inputline.Split(' ');
                var currentKey = inputData[0];
                var currentValue = int.Parse(inputData[1]);
                if (!register.ContainsKey(currentKey))
                {
                    register[currentKey] = new List<int>();
                    register[currentKey].Add(currentValue);
                }
                else
                {
                    if (!register[currentKey].Contains(currentValue))
                    {
                        register[currentKey].Add(currentValue);
                    }
                }
                inputline = Console.ReadLine();
            }
            foreach (var entry in register)
            {
                var entryValues = entry.Value;
                var sum = 0;
                for (int i = 0; i < entryValues.Count; i++)
                {
                    sum += entryValues[i];
                }
                var bigShell = 0;
                if (entryValues.Count < 2)
                {
                    bigShell = sum;
                }
                else
                {
                    bigShell = sum - (sum / entryValues.Count);
                }

                Console.WriteLine($"{entry.Key} -> {string.Join(", ", entryValues)} ({bigShell})");
            }
        }
    }
}