diff --git a/graphs_trees/tree_height/height_challenge.ipynb b/graphs_trees/tree_height/height_challenge.ipynb
index a8a33c4..5312208 100644
--- a/graphs_trees/tree_height/height_challenge.ipynb
+++ b/graphs_trees/tree_height/height_challenge.ipynb
@@ -37,6 +37,8 @@
     "* Is this a binary tree?\n",
     "    * Yes\n",
     "* Can we assume we already have a Node class with an insert method?\n",
+    "    * Yes\n",
+    "* Can we assume this fits memory?\n",
     "    * Yes"
    ]
   },
@@ -152,21 +154,21 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 2",
+   "display_name": "Python 3",
    "language": "python",
-   "name": "python2"
+   "name": "python3"
   },
   "language_info": {
    "codemirror_mode": {
     "name": "ipython",
-    "version": 2
+    "version": 3
    },
    "file_extension": ".py",
    "mimetype": "text/x-python",
    "name": "python",
    "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython2",
-   "version": "2.7.10"
+   "pygments_lexer": "ipython3",
+   "version": "3.5.0"
   }
  },
  "nbformat": 4,
diff --git a/graphs_trees/tree_height/height_solution.ipynb b/graphs_trees/tree_height/height_solution.ipynb
index 520b66c..37e8501 100644
--- a/graphs_trees/tree_height/height_solution.ipynb
+++ b/graphs_trees/tree_height/height_solution.ipynb
@@ -36,6 +36,8 @@
     "* Is this a binary tree?\n",
     "    * Yes\n",
     "* Can we assume we already have a Node class with an insert method?\n",
+    "    * Yes\n",
+    "* Can we assume this fits memory?\n",
     "    * Yes"
    ]
   },
@@ -94,7 +96,7 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "Writing height.py\n"
+      "Overwriting height.py\n"
      ]
     }
    ],
@@ -190,21 +192,21 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 2",
+   "display_name": "Python 3",
    "language": "python",
-   "name": "python2"
+   "name": "python3"
   },
   "language_info": {
    "codemirror_mode": {
     "name": "ipython",
-    "version": 2
+    "version": 3
    },
    "file_extension": ".py",
    "mimetype": "text/x-python",
    "name": "python",
    "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython2",
-   "version": "2.7.10"
+   "pygments_lexer": "ipython3",
+   "version": "3.5.0"
   }
  },
  "nbformat": 4,