SUM of the same cell across multiple sheets?

Hello, I have a Daily Sales Report workbook with 1 sheet for each day; 1.7.2024, 2.7.2024, etc.

I would like to sum all the values of e.g. cell I4 for a whole month of sheets; 1.7.2024 - 31.7.2024

I was able to use a custom function to return the list of sheet names and then reference one cell using

=indirect(H$3&"!"&"I4")

Where H3 is the first sheet name in the list and I4 is the cell value I want to use.

So I would like a formula to add all the values in I4 from H3:H33.

Thank you for any help!