diff --git a/index.ipynb b/index.ipynb
index f20dfd8fae5..6f1030ed19a 100644
--- a/index.ipynb
+++ b/index.ipynb
@@ -55,7 +55,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 2,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -78,7 +78,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 3,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -127,11 +127,22 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "italy = None # 'Italy'\n",
+   "execution_count": 4,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'Italy'"
+      ]
+     },
+     "execution_count": 4,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "italy = countries[-3] # 'Italy'\n",
     "italy"
    ]
   },
@@ -144,9 +155,20 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 5,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'Italy'"
+      ]
+     },
+     "execution_count": 5,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "italy # 'Italy'"
    ]
@@ -160,11 +182,22 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "mexico = None\n",
+   "execution_count": 6,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'Mexico'"
+      ]
+     },
+     "execution_count": 6,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "mexico = countries[3]\n",
     "mexico"
    ]
   },
@@ -177,11 +210,22 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "kindof_neighbors = None\n",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "['USA', 'Argentina', 'Mexico', 'USA', 'Morocco']"
+      ]
+     },
+     "execution_count": 7,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "kindof_neighbors = countries[1:6]\n",
     "kindof_neighbors"
    ]
   },
@@ -201,11 +245,11 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 17,
    "metadata": {},
    "outputs": [],
    "source": [
-    "None # add code here"
+    "countries.append('Malta')"
    ]
   },
   {
@@ -217,11 +261,11 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 18,
    "metadata": {},
    "outputs": [],
    "source": [
-    "None # add code here"
+    "countries.append('Thailand')"
    ]
   },
   {
@@ -233,9 +277,33 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 19,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "['Croatia',\n",
+       " 'USA',\n",
+       " 'Argentina',\n",
+       " 'Mexico',\n",
+       " 'USA',\n",
+       " 'Morocco',\n",
+       " 'New Mexico',\n",
+       " 'Finland',\n",
+       " 'Argentina',\n",
+       " 'Italy',\n",
+       " 'Canada',\n",
+       " 'South Korea',\n",
+       " 'Malta',\n",
+       " 'Thailand']"
+      ]
+     },
+     "execution_count": 19,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "countries \n",
     "# ['Croatia', 'USA', 'Argentina', 'Mexico', 'USA', 'Morocco', 'New Mexico', 'Finland', \n",
@@ -251,18 +319,42 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 20,
    "metadata": {},
    "outputs": [],
    "source": [
-    "None # add code here"
+    "countries[6] = ('USA')"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 21,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "['Croatia',\n",
+       " 'USA',\n",
+       " 'Argentina',\n",
+       " 'Mexico',\n",
+       " 'USA',\n",
+       " 'Morocco',\n",
+       " 'USA',\n",
+       " 'Finland',\n",
+       " 'Argentina',\n",
+       " 'Italy',\n",
+       " 'Canada',\n",
+       " 'South Korea',\n",
+       " 'Malta',\n",
+       " 'Thailand']"
+      ]
+     },
+     "execution_count": 21,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "countries \n",
     "# ['Croatia', 'USA', 'Argentina', 'Mexico', 'USA', 'Morocco', 'USA', 'Finland', \n",
@@ -278,9 +370,32 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 23,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "['Croatia',\n",
+       " 'USA',\n",
+       " 'Argentina',\n",
+       " 'Mexico',\n",
+       " 'USA',\n",
+       " 'Morocco',\n",
+       " 'USA',\n",
+       " 'Finland',\n",
+       " 'Argentina',\n",
+       " 'Italy',\n",
+       " 'Canada',\n",
+       " 'South Korea',\n",
+       " 'Malta']"
+      ]
+     },
+     "execution_count": 23,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "countries = ['Croatia',\n",
     " 'USA',\n",
@@ -324,18 +439,38 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 26,
    "metadata": {},
    "outputs": [],
    "source": [
-    "unique_countries = None"
+    "unique_countries = set(countries)"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 27,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "{'Argentina',\n",
+       " 'Canada',\n",
+       " 'Croatia',\n",
+       " 'Finland',\n",
+       " 'Italy',\n",
+       " 'Malta',\n",
+       " 'Mexico',\n",
+       " 'Morocco',\n",
+       " 'South Korea',\n",
+       " 'USA'}"
+      ]
+     },
+     "execution_count": 27,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "unique_countries  # ['USA', 'Finland', 'Argentina', 'South Korea', 'Morocco',\n",
     "#'Croatia','Mexico','Malta','Italy','Canada']"
@@ -350,11 +485,22 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "num_of_repeats = None\n",
+   "execution_count": 31,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "3"
+      ]
+     },
+     "execution_count": 31,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "num_of_repeats = len(countries) - len(unique_countries)\n",
     "num_of_repeats # 3"
    ]
   },
@@ -391,7 +537,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.4"
+   "version": "3.6.6"
   }
  },
  "nbformat": 4,