Determine whether the following are well-formed formulae (WFF); if it's not a WFF, circle
the defect and state the problem; if it's OK, then just write "WFF."

11. ~Dv~[(If P then Q) • (if T then R)]
12. M ~ (If N then Q) v (~C • D)
13. [(D • Q if/then (PvE)] v [If A then (• H)]