diff --git a/.DS_Store b/.DS_Store
index 202195e..0d6c775 100644
Binary files a/.DS_Store and b/.DS_Store differ
diff --git a/lab/LAB_01.md b/lab/LAB_01.md
index a79f2f3..0ffde06 100644
--- a/lab/LAB_01.md
+++ b/lab/LAB_01.md
@@ -2,7 +2,7 @@
 
 Do wykonania ćwiczeń należy skopiować repozytorium:
 ```shell
-git clone https://git.wmi.amu.edu.pl/bigdata/apache_hadoop
+git clone https://git.wmi.amu.edu.pl/s1201683/hadoop_zaliczenie
 ```
 Celem ćwiczenia jest zaprezentowanie aplikacji w oparciu o algorytm MapReduce z wykorzystaniem:
 
@@ -18,7 +18,7 @@ WordCount jest „odpowiednikiem Hello World” w świecie Big Data. Ćwiczenie
 Aby wykonać ćwiczenia, należy skopiować folder _books_ do systemu HDFS:
 ```
 hdfs dfs -mkdir tmp
-hdfs dfs -copyFromLocal ~/apache_hadoop/mr/books tmp/books
+hdfs dfs -copyFromLocal ~/hadoop_zaliczenie/mr/books tmp/books
 ```
 ## 1.WordCount – Hadoop Streaming
 Hadoop streaming umożliwia użytkownikom wykorzystanie mappera i reducera napisanego w dowolnym języku programowania. Jedynym wymaganiem jest obecność interpretera na każdym z węzłów.
diff --git a/mr/.DS_Store b/mr/.DS_Store
index 0f95520..5117ba3 100644
Binary files a/mr/.DS_Store and b/mr/.DS_Store differ
diff --git a/mr/python/.DS_Store b/mr/python/.DS_Store
new file mode 100644
index 0000000..5008ddf
Binary files /dev/null and b/mr/python/.DS_Store differ
diff --git a/mr/python/mapper.py b/mr/python/mapper.py
index 77d44f4..8668ac8 100644
--- a/mr/python/mapper.py
+++ b/mr/python/mapper.py
@@ -2,13 +2,17 @@
 import sys
 import re
 
-
+# input comes from STDIN (standard input)
 for line in sys.stdin:
-
+    # remove leading and trailing whitespace
     line = line.strip()
-    words = re.findall(r'\b\w+\b', line)
-
+    # split the line into words
+    words = re.findall(r'\b\w+\b', line)  # using regex to find words
+    # increase counters
     for word in words:
-
+        # apply regex to remove non-alphanumeric characters and convert to lowercase
         word = re.sub(r'[^a-zA-Z0-9]', '', word).lower()
+        # write the results to STDOUT (standard output);
+        # what we output here will be the input for the
+        # Reduce step, i.e. the input for reducer.py
         print('%s\t%s' % (word, 1))
diff --git a/mr/python/reducer.py b/mr/python/reducer.py
index 6bf6ae3..e1ce1be 100644
--- a/mr/python/reducer.py
+++ b/mr/python/reducer.py
@@ -1,4 +1,4 @@
-
+#!/usr/bin/env python
 from operator import itemgetter
 import sys