Problems getting ChatGPT to summarize to an exact number of characters

Hi

I am trying to create a plugin to use in wordpress that will summarize post titles to 38 characters, but through all my attempts, i cannot get ChatGPT to consistently match my required character count.

To avoid my coding being the issue, if i use the ChatGPT website , or any of the playgrounds, i still cannot get it to summarize consistantly to 38 characters.

Sometimes the answers are 30 in length, the next 44. I have tried many different expressions to try and achieve this but nothing is working. A few examples can be seen below

Summarize " Xbox saves the summer with a solid showcase that channels the E3 of old" to 38 characters

Summarize " Xbox saves the summer with a solid showcase that channels the E3 of old" using only 38 characters

Summarize " Xbox saves the summer with a solid showcase that channels the E3 of old" using a maximum of 38 characters. Do not exceed 38 characters or use less than 38 characters

Regardless of what i type, my answers never get the 38 characters , they may get it 1 in 10 attempts, but i am wanting a 100% hit rate, even 95% would do. I am trying to abbreviate news headlines/ tweets for a site that i am making.

Any help / advice would be massively welcomed

Thanks