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 rx = "ATG(?:(?!ATG)[ATG]{3})*?(?:TAG|TAA|TGA)";
		String s = "ATGTTGTGATGT, ATGATGTTGTGATGT, ATGATGTTGTGATGT";
		Pattern pattern = Pattern.compile(rx);
		Matcher matcher = pattern.matcher(s);
		while (matcher.find()) {
    			System.out.println(matcher.group(0));
    		}
	}
}

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