import java.io.File;
import java.io.FileNotFoundException;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Test {
    public static void main(String[] args) throws FileNotFoundException {
        Set<String> set = new HashSet<String>();
        
        Scanner scanner = new Scanner(new File("a.txt"));
        while (scanner.hasNextLine()) {
            String line = scanner.nextLine().trim();
            if (line.matches("\\d+:\\d+")) {
                set.add(line);
            }
        }
        scanner.close();
        
        System.out.println(set);
    }
}