Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to identify cat stool problems [title] Notice your cat's litter box behavior. [step] You can tell a lot about your cat by how it acts in and around its litter box. Watch how often your cat goes to the bathroom.

Ending1: Listen for any crying or painful sounds while your cat is using the litter box. Notice if bathroom trips were successful or not. Ending2: Cats are naturally sensitive to smell, so they may go to the bathroom regularly in your home. Watch your cat when you walk past it. Ending3: Most cats go to the bathroom outside in their litter box, so check your cat's litter box at least once a day. [substeps] If your cat goes from the bathroom to the bedroom while you are sleeping or if it stays back and doesn't go to the bathroom in the middle of the night, you may have a problem. Ending4: If it comes back wet wet at night to use the bathroom, it might be going to the bathroom there. [substeps] Also pay attention to how the litter box smells.

Answer format: ending1/ending2/ending3/ending4