Chocona

Description
Chocona is a binary determination puzzle in which the cells in a grid are split into either shaded or unshaded.

Rules
The objective is to shade some cells, subject to the following rules:


 * 1) Numbers indicate how many shaded cells are in a region.
 * 2) Shaded cells must form rectangles, independently of the region borders.
 * 3) Shaded rectangles must not touch horizontally or vertically.

Example
A standard 10x10 chocona and its solution.