Please can someone tell me how this is draw by repetition?

Hi there

I thought I understood the rules for draw by repetition, but I was playing white versus Stockfish (with the computer set at a lowly 17.5% of full strength) and it suddenly declared draw by repetition, when I felt I had a good chance of beating it. Please can someone explain to me how moving my rook at the end forced this into a draw?

Thanks for your help!

[Event "?"]
[Site "?"]
[Date "2019.09.10"]
[Round "?"]
[White "Player"]
[Black "Stockfish 10 64 (17.5%)"]
[Result "1/2-1/2"]
[TimeControl "60/120"]

1. d4 e6 2. Nf3 Nf6 3. c4 b6 4. g3 Bb7 5. Bg2 Be7 6. Nc3 Na6 7. O-O O-O 8. a3 Ne4 9. Qc2 d5 10. cxd5 exd5 11. Nh4 Bxh4 12. Nxe4 c5 13. Nxc5 Nxc5 14. dxc5 Be7 15. cxb6 Bd6 16. bxa7 Rxa7 17. Qb3 Re8 18. Be3 d4 19. Bxd4 Bxg2 20. Kxg2 Ra6 21. Qc4 Qa8+ 22. Kg1 Ra4 23. Qd3 Rd8 24. e3 Bc5 25. Qb5 Ra5 26. Qd3 Ra7 27. Qc3 Bxd4 28. exd4 h5 29. h4 Rad7 30. Rfd1 Rd6 31. b4 Qa4 32. Qc5 Rd5 33. Qc7 Ra8 34. Qc4 Rad8 35. Qc7 Qe8 36. Re1 Qa4 37. Red1 1/2-1/2

While you're at it, please can you tell me why pasting that pgn code into this forum using "Insert chess game or diagram" isn't working for me? I just clicked that button, then Load pgn, pasted it in, and clicked Load again. It just showed a blank chess board in the post, so I deleted it.

Thanks!

Neil

Position 33, 35 and 37 are exactly the same, with black to move in each. Therefore a draw by triple repetition of position that was claimed by the engine.

Ah! Thank you!