Where do I find Live Merchant ID

[elegilly]

Peaceful Greetings:

I am updating from PayPal Standard. 

Live Merchant ID is being requested.

It says the Code should be 15 digits.

When i go to my account >Business Profile>Business Information I only see

PayPal Merchant ID which is 13 digits. 

Where do i find the requested code in my account?

[elegilly]

EDIT*  Further...when using my \merchant ID - I get this error:

I have used this account successfully previously.  There have been no changes.

INVALID_PARAMETER_SYNTAX The value of a field does not conform to the expected format.
INVALID_STRING_LENGTH The value of a field is either too short or too long.