import java.util.regex.*;
import java.util.*;
import java.lang.*;
import java.io.*;
 
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String text = "avcavf 213.123.11.255aoegger";
		String octet = "(?:25[0-5]|2[0-4]\\d|[01]?\\d\\d?)";
		Pattern p = Pattern.compile("(?<!\\d)" + octet + "(?:\\." + octet +"){3}(?!\\d)");
		Matcher m = p.matcher(text);
		System.out.println(m.find() ? m.group() : "Not found");
	}
}

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