diff --git a/recursive_count_th/count_th.py b/recursive_count_th/count_th.py
index 07456a00b..ecad6ac16 100644
--- a/recursive_count_th/count_th.py
+++ b/recursive_count_th/count_th.py
@@ -5,6 +5,15 @@
 '''
 def count_th(word):
     
-    # TBC
+    # Verify if the length of the word is not less than "th"; else, it contains it
     
-    pass
+    if len(word) < len('th'):
+        return 0
+
+    #Furthermore, verify if the first two letters equals "th", return 1 
+    elif word[:2] == 'th':
+        return count_th(word[2:]) + 1
+
+    #Else, proceed with the next letter of the word
+    else:
+        return count_th(word[1:])
diff --git a/robot_sort/robot_sort.py b/robot_sort/robot_sort.py
index db6b1985b..81c5df273 100644
--- a/robot_sort/robot_sort.py
+++ b/robot_sort/robot_sort.py
@@ -97,7 +97,28 @@ def sort(self):
         Sort the robot's list.
         """
         # Fill this out
-        pass
+        self.set_light_on()
+
+        while self.light_is_on():
+            self.set_light_off()
+
+            while self.can_move_right():
+                self.move_right()
+
+                if self.compare_item() == 1:
+                    self.swap_item()
+                    self.set_light_on()
+
+            while self.can_move_left():
+                self.swap_item()
+                self.move_left()
+
+                if self.compare_item() == -1:
+                    self.swap_item()
+                    self.set_light_on()
+                self.move_right()
+                self.swap_item()
+                self.move_left()
 
 
 if __name__ == "__main__":