diff --git a/app/main.py b/app/main.py
index 4af4456..c39f0b7 100644
--- a/app/main.py
+++ b/app/main.py
@@ -4,6 +4,7 @@
 ###########################################################################
 from flask import abort, jsonify
 from markupsafe import escape
+from collections import Counter
 from Login import *
 from Article import *
 import Yaml
@@ -58,6 +59,12 @@ def appears_in_test(word, d):
     else:
         return ','.join(d[word])
 
+
+def good_word(word):
+    return len(word) < len('Pneumonoultramicroscopicsilicovolcanoconiosis') \
+        and Counter(word).most_common(1)[0][1] <= 4
+
+
 @app.route("/mark", methods=['GET', 'POST'])
 def mark_word():
     '''
@@ -99,7 +106,7 @@ def mainpage():
     if request.method == 'POST':  # when we submit a form
         content = escape(request.form['content'])
         f = WordFreq(content)
-        lst = f.get_freq()
+        lst = [ t for t in f.get_freq() if good_word(t[0]) ] # only keep normal words
         # save history
         d = load_freq_history(path_prefix + 'static/frequency/frequency.p')
         lst_history = pickle_idea.dict2lst(d)