MIAMI — This is about as simple as math gets in the NBA: — The league allows teams to have up to three players under two-way contracts at a time. — The Heat have three players already under such contracts at the moment. — Forward Cole Swider is coming off a two-way contract and has a qualifying offer in place for another Heat two-way contact, even with a no-vacancy sign out when it comes to such a Heat opportunity. So, no, the math doesn’t feel quite right, with the Heat essentially extending a promissory note to the second-year shooting specialist for something that doesn’t quite exist at the moment. “I’m just worried about just developing,” Swider said Thursday after completing the first practice of the Heat’s summer program, “I can’t control what contract I’m going to sign or not going to sign.