Get ContactID when a Contact is updated

Get ContactID when a Contact is updated

I'm using this code from a previous question to update a field in a Contact whenever a Contact receives an email:
  2. //access the emails field from the Contact
  3. emailInfo = zoho.crm.getRelatedRecords("Emails", "Contacts", --yourcontactID--);
  4. //create a list of every email from that Contact
  5. emailList = emailInfo.get("email_related_list");
  6. //count the number of emails in that list
  7. count = emailList.size();
  8. //if the number of the emails in the list is greater than 0, get the most recent email's Created Time date
  9. if(count > 0)
  10. {
  11. mostRecentDate = emailList.get(0).get("Created Time");
  12. for each i in emailList
  13. {
  14. if(i.get("Created Time") > mostRecentDate)
  15. {
  16. mostRecentDate = i.get("Created Time");
  17. }
  18. }
  19. // Update the Last Contact Date with that date
  20.         mapUp = Map();
  21. mapUp.put("Latest_Outreach",mostRecentDate);
  22.         response = zoho.crm.updateRecord("Contacts", --yourcontactID--);
  23. }
  24. return;
Where it says "--yourcontactID--", I need to get the specific Contact's ID as a variable into that space. So I need a function that, when an action happens -- in this case, when a Contact gets an new email attached to it-- that Contact's ID is captured and that ID is then used in the code above.

Here's how I'd like it to work:
1. An email is attached to a Contact using the BCC dropbox
2. A workflow action is triggered and runs the code above
3. At the start of that code, the ContactID is captured and set to a variable
4. The rest of the above code executes