Hello,
I have been using MailWizz to send newsletters.
I would like to create a custom field "SENT_TIMES" which records how many times a subscriber have received newsletters from us.
So each time I send a newsletter, I plan to set `Change subscriber custom field value upon campaign sent` to increment "SENT_TIMES" like follows.

But my tests show that it does not work. It set the value to literally `[SENT_TIMES]+1` rather than numeric values, which is not what I wanted.
Does anyone know how to achieve this?
I have been using MailWizz to send newsletters.
I would like to create a custom field "SENT_TIMES" which records how many times a subscriber have received newsletters from us.
So each time I send a newsletter, I plan to set `Change subscriber custom field value upon campaign sent` to increment "SENT_TIMES" like follows.

But my tests show that it does not work. It set the value to literally `[SENT_TIMES]+1` rather than numeric values, which is not what I wanted.
Does anyone know how to achieve this?