diff --git a/07/main.rs b/07/main.rs
index 13137af..02d8178 100644
--- a/07/main.rs
+++ b/07/main.rs
@@ -42,20 +42,17 @@ fn part_one() {
                         if f < 100000 {
                             sum += f
                         }
-                        let mut p = stack.pop().unwrap();
-                        p += f;
-                        stack.push(p);
+                        let last_on_stack = stack.len() - 1;
+                        stack[last_on_stack] += f;
                     }
                     s if s.starts_with("$ cd ") => {
                         stack.push(0);
                     }
                     s => {
                         // otherwise it must be a file
-                        let mut f = stack.pop().unwrap();
                         let mut sp = s.split(" ");
-                        let size = sp.next().unwrap().parse::<u32>().unwrap();
-                        f += size;
-                        stack.push(f);
+                        let last_on_stack = stack.len() - 1;
+                        stack[last_on_stack] += sp.next().unwrap().parse::<u32>().unwrap();
                     }
                 };
             }
@@ -80,20 +77,17 @@ fn part_two() {
                         if f > space_to_free && f < to_delete {
                             to_delete = f
                         }
-                        let mut p = stack.pop().unwrap();
-                        p += f;
-                        stack.push(p);
+                        let last_on_stack = stack.len() - 1;
+                        stack[last_on_stack] += f;
                     }
                     s if s.starts_with("$ cd ") => {
                         stack.push(0);
                     }
                     s => {
                         // otherwise it must be a file
-                        let mut f = stack.pop().unwrap();
                         let mut sp = s.split(" ");
-                        let size = sp.next().unwrap().parse::<u32>().unwrap();
-                        f += size;
-                        stack.push(f);
+                        let last_on_stack = stack.len() - 1;
+                        stack[last_on_stack] += sp.next().unwrap().parse::<u32>().unwrap();
                     }
                 };
             }