import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.*;
 
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String s = "su,sa,we";
		String day = "fr|sa|su|mo|tu|we|th";
		String pattern = "(?!.*\\b([a-z]{2})\\b.*\\b\\1\\b)(?:" + day + ")?(?:,(?:" + day + ")){0,5}";
		if (s.matches(pattern)) {
		    System.out.println("Valid!");
		} else {
		    System.out.println("Invalid!");
		}
	}
}

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