base_first	unseen	2
base_first	seen	1
base_first	unseen	1
base_last	seen	2
base_last	unseen	1
base_last	unseen	1
base_last	seen	3
base_last	seen	1
base_first	seen	3
base_last	seen	2
base_last	unseen	2
base_last	seen	2
base_last	unseen	3
base_first	unseen	1
base_first	seen	2
base_last	unseen	2
base_first	seen	1
base_first	seen	2
base_last	seen	1
base_first	unseen	3
base_last	unseen	3
base_last	unseen	1
base_first	seen	3
base_last	seen	1
base_last	unseen	2
base_first	unseen	2
