import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
 
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String thread = "From: Demo Name\n" +
                "Sent: Wednesday, January 18, 2023 2:56 PM\n" +
                "To: demo@myweb.com <demo@myweb.com>\n" +
                "Subject: Demo Issue";
        String regEX = "(?:^[a-z]+:\\h.*\\R){2,4}Subject:.*";
        Pattern pattern = Pattern.compile(regEX, Pattern.CASE_INSENSITIVE | Pattern.MULTILINE);
        Matcher matcher = pattern.matcher(thread);
        System.out.println(matcher.find());
	}
}

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