/**
 * Returns number of cells needed for given size of the widget.
 * 
 * @param size Widget size in dp.
 * @return Size in number of cells.
 */
private static int getCellsForSize(int size) {
	int n = 2;
	while (70 * n - 30 < size) {
		++n;
	}
	return n - 1;
}