I would like to create a script activity in automation in order to update a Sales Object.

this is an exemple of script, how can i update this script to be accepted as A SSJS script in script activity?

%%[

var @rowCount
set @rowCount = DataExtensionRowCount("ENT.My_DE")

var @nmaratasDE, @rsRow, @i, @Contact_ID, @PhoneNumber
SET @nmaratasDE = LookupRows("nmaratasDE")

IF RowCount(@nmaratasDE) > 0 THEN
FOR @i = 1 to RowCount(@nmaratasDE) DO
SET @rsRow = Field(Row(@nmaratasDE, @i))
SET @Contact_ID = Field(@rsRow, "ContactID")
SET @PhoneNumber = Field(@rsRow, "MobileNumber")



)


set @result = UpdateSingleSalesforceObject('IN_Contact__c',@Contact_ID,Phone_Num_c,@PhoneNumber)


]%%