import java.util.*;
import java.lang.*;

class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
	    String foo = "some text I don't know <pre>the text I want to get</pre><pre>Some more text I want to get</pre> some text I don't know";
	    int preStart = foo.indexOf("<pre>");
	    int preEnd = foo.indexOf("</pre>");
	    
	    if (preStart > -1 && preEnd > preStart)
	    {
	        String inBetweenTags = foo.substring(preStart + 5, preEnd);
	        System.out.println(inBetweenTags);
	    }
	}
}