How to access to the elements of HashMap in HandleBars (hbs) file for Rust

I have a variable defined as HashMap in rs file:

sampleDir: HashMap<String, String>

and is initialized as the following (for example), it's two dimensional:

sampleDir: HashMap::from([((&"aa").to_string(), (&"ab").to_string()),
                    ((&"ba").to_string(), (&"bb").to_string()),
                    ((&"ca").to_string(), (&"cb").to_string())].iter().cloned().collect())

I'm trying to access to those two elements in sampleDir in hbs file (for example):

{{#each sampleDir as |s|}}
        <tr>
            <th>
                how can I access to the first element? i.e. aa, ba, ca
            </th>
            <td style="width: 100%;">
                how can I access to the second element? i.e. ab, bb, cb
            </td>
        </tr>
{{/each}}

I use this like the following, but it only access to the second element, i.e. ab, bb, cb:

{{#each sampleDir as |s|}}
            <tr>
                <th>
                    {{this}}
                </th>
                <td style="width: 100%;">
                    {{this}}
                </td>
            </tr>
{{/each}}

Any help would be greatly appreciated!

After some investigation, here is the solution:

{{#each sampleDir as |s|}}
        <tr>
            <th>
                {{@key}}
            </th>
            <td style="width: 100%;">
                {{this}}
            </td>
        </tr>
{{/each}}