import java.util.*;
import java.lang.*;
import java.io.*;
 
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner input = new Scanner(System.in);
		String followers = input.nextLine().trim().replaceAll("\"","");
		HashSet<String> f1 = new HashSet<>();
		for(String s : followers.split(",")) f1.add(s);
 
		String following = input.nextLine().trim().replaceAll("\"","");
		while(following.isEmpty()) following = input.nextLine().trim().replaceAll("\"","");
		System.out.println("People who dont follow you back:\n");
		for(String s : following.split(",")) {
			if(!f1.contains(s)) System.out.println(s);
		}
	}
}

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name1,name2
name2,name3