using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
 
public class Test
{
	public static void Main()
	{
		var s = @"Text user1@company.com here user2@company.com and user3@company.com here user1@private.com more user2@private.com";
    	var result = s.Split().Where(m => 
    		Regex.IsMatch(m, @"^\S+@\S+\.\S+$") && m != "user2@private.com" && !m.StartsWith("user1@"));
        foreach (var str in result)
        	Console.WriteLine(str);
	}
}

dXNpbmcgU3lzdGVtOwp1c2luZyBTeXN0ZW0uQ29sbGVjdGlvbnMuR2VuZXJpYzsKdXNpbmcgU3lzdGVtLklPOwp1c2luZyBTeXN0ZW0uTGlucTsKdXNpbmcgU3lzdGVtLlRleHQuUmVndWxhckV4cHJlc3Npb25zOwoKcHVibGljIGNsYXNzIFRlc3QKewoJcHVibGljIHN0YXRpYyB2b2lkIE1haW4oKQoJewoJCXZhciBzID0gQCJUZXh0IHVzZXIxQGNvbXBhbnkuY29tIGhlcmUgdXNlcjJAY29tcGFueS5jb20gYW5kIHVzZXIzQGNvbXBhbnkuY29tIGhlcmUgdXNlcjFAcHJpdmF0ZS5jb20gbW9yZSB1c2VyMkBwcml2YXRlLmNvbSI7CiAgICAJdmFyIHJlc3VsdCA9IHMuU3BsaXQoKS5XaGVyZShtID0+IAogICAgCQlSZWdleC5Jc01hdGNoKG0sIEAiXlxTK0BcUytcLlxTKyQiKSAmJiBtICE9ICJ1c2VyMkBwcml2YXRlLmNvbSIgJiYgIW0uU3RhcnRzV2l0aCgidXNlcjFAIikpOwogICAgICAgIGZvcmVhY2ggKHZhciBzdHIgaW4gcmVzdWx0KQogICAgICAgIAlDb25zb2xlLldyaXRlTGluZShzdHIpOwoJfQp9