Logic Puzzle

This is one of my favorite puzzles. You can use any number of 'and' and 'or' gates, with any number of inputs each, but only two 'not' gates. You must build a circuit that computes for inputs A, B, and C, the three separate values not A, not B, and not C. Essentially, can you invert three signals, using two inverters and any number of `and' and `or' gates?

Once you have solved that, the next question is, can you use this circuit recursively to build 4, then 6, then 9, then 13, then 19, then 28, then 42, and so on, effective inverters? In other words, can you say that any combinational circuit can be constructed with just two inverters?