I'm training for a marathon, and the weekend I'm supposed to run 14 miles (not for the first time, it's the weekend after I'm planning to run a 20 mile long run), there's a half marathon taking place in my city. I'm thinking about signing up and running it. It takes place about a month before my marathon. Would it be okay to run? Also, since I'm scheduled to run 14 miles on that day, should I just run a mile beforehand or something so I'm not missing out on that mileage?