Is it correct?
p → q, ¬p → r, ¬q → ¬r ⊢ q
1) p -> q premise
2) ¬p → r premise
3) ¬q → ¬r premise
4) ¬q assumption
5) ¬p MT 1,4
6) r e2 2,5
7) ¬q assumption
8) ¬r e2 3,7
9) ⊥ ¬e 6,8
10 ¬q assumption
11) q ¬e 9, 10
I believe it is true. Could you please help?