diff --git a/src/day07.rs b/src/day07.rs
index ef71129..976c4a0 100644
--- a/src/day07.rs
+++ b/src/day07.rs
@@ -113,12 +113,7 @@ fn compute_dir_sizes(input: &[CliOperation]) -> Tree<(usize, usize)> {
         match op {
             CliOperation::Cd(dir) => {
                 if dir == ".." {
-                    current_node = tree
-                        .ancestor_ids(&current_node)
-                        .unwrap()
-                        .next()
-                        .unwrap()
-                        .clone();
+                    current_node = tree.get(&current_node).unwrap().parent().unwrap().clone();
                 } else {
                     current_node = tree
                         .insert(Node::new((0, 0)), InsertBehavior::UnderNode(&current_node))