如何从C#中的字符串中提取一段时间之前的文本？

using System;

public class Program
{
    public static void Main()
    {
        string input = "2022-01-01 12:00:00 This is the text to extract.";
        DateTime dateTime = DateTime.Parse(input.Substring(0, 19));
        TimeSpan timeSpan = new TimeSpan(1, 0, 0, 0); // 提取一年前的文本
        DateTime targetDateTime = dateTime - timeSpan;
        string targetString = targetDateTime.ToString("yyyy-MM-dd HH:mm:ss");
        string result = input.Substring(targetString.Length);
        Console.WriteLine(result);
    }
}