1 files changed, 5 insertions, 5 deletions
diff --git a/prolog/problems/trees/insertbt_3/en.py b/prolog/problems/trees/insertbt_3/en.py
index 08eb2cd..c0fa47c 100644
--- a/prolog/problems/trees/insertbt_3/en.py
+++ b/prolog/problems/trees/insertbt_3/en.py
@@ -6,11 +6,11 @@ slug = 'insert an element into a binary tree'
 description = '''\
 <p><code>insertBT(X, T, NewT)</code>: the binary tree <code>NewT</code> is obtained from <code>T</code> by inserting the element <code>X</code> at a certain position. This is the opposite of the predicate <code>deleteBT/3</code>. Your code should generate all valid solutions.</p>
 <pre>
-  ?- insertBT(2, b(nil,1,nil), T).
-    T = b(b(nil,1,nil),2,nil) ;
-    T = b(nil,2,b(nil,1,nil)) ;
-    T = b(b(nil,2,nil),1,nil) ;
-    T = b(nil,1,b(nil,2,nil)).
+?- insertBT(2, b(nil,1,nil), T).
+  T = b(b(nil,1,nil),2,nil) ;
+  T = b(nil,2,b(nil,1,nil)) ;
+  T = b(b(nil,2,nil),1,nil) ;
+  T = b(nil,1,b(nil,2,nil)).
 </pre>'''
 
 hint = {}