How can I improve this code ?

Question

I'm trying to solve the symbols codecoach using c#, but when I use Regex it gives spaces. And it fails all the test cases.using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Text.RegularExpressions;

namespace SoloLearn
{
class Program
{
static void Main(string[] args)
{
string input = Console.ReadLine();
string result = Regex.Replace(input, "[^a-zA-Z0-9_]+"," ");
Console.WriteLine(result);
}
}

}

Answer 1

input.Trim() or result.Trim() depending on where you wanna elimnate the space

Answer 2

string result =input.Replace(" ","");