SimpleXML problem print key value

I have been searching google for over an hour and am frustrated, This seems so simple. All I am trying to print is my accountId. Here is the xml i am being returned from the server:

SimpleXMLElement Object
(
[accounts] => SimpleXMLElement Object
    (
        [account] => SimpleXMLElement Object
            (
                [billingStreet] => SimpleXMLElement Object
                    (
                    )

                [billingCity] => SimpleXMLElement Object
                    (
                    )

                [billingState] => SimpleXMLElement Object
                    (
                    )

                [billingPostalCode] => SimpleXMLElement Object
                    (
                    )

                [billingCountry] => SimpleXMLElement Object
                    (
                    )

                [city] => Los Angeles
                [accountId] => XXXXX
                [companyName] => SimpleXMLElement Object
                    (
                    )

                [country] => United States
                [email] => XXXXX
                [enabled] => 1
                [fax] => SimpleXMLElement Object
                    (
                    )

                [firstName] => XXXXX
                [lastName] => XXXXX
                [multiClientFolder] =>开发者_JS百科 0
                [multiUser] => 0
                [phone] => XXXXX
                [postalCode] => XXXXX
                [state] => CA
                [street] => XXXXX
                [title] => SimpleXMLElement Object
                    (
                    )

                [accountType] => 0
                [subscriberLimit] => 250000
            )

    )

[total] => 1
[limit] => 20
[offset] => 0
)

All i want is accountId. I am using this and it doesnt print anything:

$ch=curl_init("https://app.sandbox.icontact.com/icp/a/");
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
$buf = curl_exec($ch);
curl_close($ch);
$xml = simplexml_load_string($buf);
$aid=$xml->$accounts->$account->$accountId;
print($aid);

i can print the entire xml array just fine with print_r though. Im not sure what i am doing wrong

Maybe $aid=$xml->accounts->account->accountId;?

If there is the possibility of getting more than one account in the response, you can add an array index to the account element:

$aid = $xml->accounts->account[0]->accountId;

Or iterate over the accounts:

foreach ($xml->accounts->account as $account) {
    ...
}

Also note that $aid will be of type SimpleXMLElement. In most cases you can use this as-is and it will be automatically cast to the appropriate type, but if you want the value as a string you can use an explicit cast:

$aid = (string) $xml->accounts->account[0]->accountId;