```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns4:query_definition xmlns:ns2="http://www.i2b2.org/xsd/cell/crc/psm/1.1/" xmlns:ns4="http://www.i2b2.org/xsd/cell/crc/psm/querydefinition/1.1/" xmlns:ns3="http://www.i2b2.org/xsd/cell/crc/psm/analysisdefinition/1.1/">
    <query_name>Princip-ICD9 (I@11:02:31</query_name>
    <query_timing>ANY</query_timing>
    <specificity_scale>0</specificity_scale>
    <panel>
        <panel_number>1</panel_number>
        <panel_timing>ANY</panel_timing>
        <panel_accuracy_scale>100</panel_accuracy_scale>
        <invert>0</invert>
        <total_item_occurrences>1</total_item_occurrences>
        <item>
            <hlevel>1</hlevel>
            <item_name>Diseases of the nervous system (g00-g99)</item_name>
            <item_key>\\ICD10_ICD9\Diagnoses\(G00-G99) Dise~j8kq\</item_key>
            <item_icon>FA</item_icon>
            <tooltip>Diagnoses \ Diseases of the nervous system (g00-g99)</tooltip>
            <class>ENC</class>
            <constrain_by_modifier>
                <modifier_name>Principal Diagnosis</modifier_name>
                <modifier_key>\\ICD10_ICD9\Principal Diagnosis\</modifier_key>
                <applied_path>\Diagnoses\(G00-G99) Dise~j8kq\%</applied_path>
            </constrain_by_modifier>
            <item_is_synonym>false</item_is_synonym>
        </item>
    </panel>
    <panel>
        <panel_number>2</panel_number>
        <panel_timing>ANY</panel_timing>
        <panel_accuracy_scale>100</panel_accuracy_scale>
        <invert>0</invert>
        <total_item_occurrences>1</total_item_occurrences>
        <item>
            <hlevel>2</hlevel>
            <item_name>ICD9 (Inpatient)</item_name>
            <item_key>\\i2b2_PROC\i2b2\Procedures\PRC\ICD9 (Inpatient)\</item_key>
            <item_icon>FA</item_icon>
            <tooltip>Procedures \ ICD9 (Inpatient)</tooltip>
            <class>ENC</class>
            <item_is_synonym>false</item_is_synonym>
        </item>
    </panel>
</ns4:query_definition>

```

I want to find all patients with a principal diagnosis of any disease of the nervous system (ICD-9 codes G00-G9) using the ICD-9 coding system for in the inpatient setting.