Breaking Up a Chocolate Bar - One puzzle a day - Puzzle Buddies

Puzzle:How many steps are required to break an m x n bar of chocolate into 1 x 1 pieces?

You can break an existing piece of chocolate horizontally or vertically.

You cannot break two or more pieces at once (so no cutting through stacks).
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Solution:

You need mn – 1 steps. By breaking an existing piece horizontally or vertically, you merely increase the total number of pieces by one. You already have 1 piece, so need mn – 1 steps to get to mn pieces.

Winner: Kasturi