C# Playground - Oracle Cloud String Filter (Interview ❤): Online Interpreter, Compiler & Editor

using System;
using System.Collections.Generic;
using System.Linq;
// https://www.sololearn.com/Discuss/800264/?ref=app
namespace SoloLearn
{
    class Program
    {
        static void Main(string[] zephyr_koo)
        {
            var paragraph = new List<string>();
            var input     = "so we started so, we start again the gain, we! never give up up! up;";
            var words     = input.Split(' ');
            foreach (var word in words)
            {
                var filteredWord = new string(word.Where(char.IsLetter).ToArray());
                if (!paragraph.Contains(filteredWord))
                {
                    paragraph.Add(word);
                }
                else
                {
                    var symbol = word.Replace(filteredWord, string.Empty);
OUTPUT