How do I delete all rows below a certain point in LibreCalc, without causing it to hang?

I did a dumb thing. I wanted to make a new column that used the same formula as an old one, but modified slightly. So I added a new column, selected a cell containing the original formula, copied it, selected the new column, and hit paste.

By pasting to the entire column, I apparently told LibreCalc to paste the formula to every cell in that theoretically infinitely-long column. It has added some huge number of rows to my document (the file size has grown from 42KB to 86MB) and LibreCalc now hangs any time I try to do almost anything with the document. What I would like to do is remove anything in any row below a certain number, but I’m not having any luck finding a way to do that without causing LibreCalc to hang. I tried:

  • Using the Undo button, to undo the paste.
  • Creating a new sheet, cutting and pasting only the data I want into it, then deleting the original sheet.
  • Selecting the entire sheet (by clicking the box in the upper left of the column and row headers) then shift-unselecting the data I want to keep and deleting the remaining selected space.

Is there anything else I can try to recover my document to a workable state?

Using Calc (because that’s the version my distro seems to have available…)

Both in Calc and Writer, Ctrl+Shift+End marks till the document end. Then you can delete.
(Corrected per comment)

this should be CTRL+SHIFT+END.

( then DEL )