How to Change Deal Name at time of Lead Conversion

How to Change Deal Name at time of Lead Conversion

Hi,
I need  Deal name to be : Lead Name + Product Name.
But at time of lead conversion it's automatically taking Lead Name in Deal Name field.
Is it possible to auto update it at time of lead conversion/deal creation.

I am using following code which is not working.

dealIdStr=input.dealId.toString();
dealDetails = zoho.crm.getRecordById("Deals", input.dealId);
module = ifnull(dealDetails.get("SEMODULE"),"");
id = ifnull(dealDetails.get("RELATEDTOID"),"");
if ( module == "Leads")
{
leadDetails = zoho.crm.getRecordById(("Leads"), id.toLong());
mp=map();
mp.put("Deal Name",ifnull(leadDetails.get("Lead Name"),"") + " " + ifnull(leadDetails.get("Product Name"),""));
update=zoho.crm.update("Deals", dealId, mp);
info mp;
info update;
}