(1) how to lock the door with 3 locks, and all 3 keys are necessary to unlock the door;
(2) how to lock the door with 3 locks, and any 1 key is necessary and sufficient to unlock the door;
(3) how to lock the door with 3 locks, and any 2 keys are necessary and sufficient to unlock the door;
(4) how to lock the door with 5 locks, and any 3 keys are necessary and sufficient to unlock the door;
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