diff --git a/Mission433Solutions.ipynb b/Mission433Solutions.ipynb
index 9ee4f3a..b915550 100644
--- a/Mission433Solutions.ipynb
+++ b/Mission433Solutions.ipynb
@@ -949,11 +949,11 @@
     "p_ham = len(ham_messages) / len(training_set_clean)\n",
     "\n",
     "# N_Spam\n",
-    "n_words_per_spam_message = spam_messages['SMS'].apply(lambda x: len(x))\n",
+    "n_words_per_spam_message = spam_messages['SMS'].apply(len)\n",
     "n_spam = n_words_per_spam_message.sum()\n",
     "\n",
     "# N_Ham\n",
-    "n_words_per_ham_message = ham_messages['SMS'].apply(lambda x: len(x))\n",
+    "n_words_per_ham_message = ham_messages['SMS'].apply(len)\n",
     "n_ham = n_words_per_ham_message.sum()\n",
     "\n",
     "# N_Vocabulary\n",