Not enough boxes to fill in SA106

I received bank interest from 4 countries. As there's only 3 boxes to fill in SA106, what can I do then?

Hi Yiu Wa Ng,
The guidance at Foreign notes Tax year 6 April 2023 to 5 April 2024 (2023–24) advises that you fill up the three rows  A - F with your foreign interest and include the remaining countries on a separate sheet of paper.  
The total figure entered in box 4 must be the total of all of the foreign interest and not just the 3 displayed.
Foreign Tax year 6 April 2023 to 5 April 2024 (2023–24).
Thank you.