diff --git a/tx b/tx
index b1c8032..48ac767 100755
--- a/tx
+++ b/tx
@@ -8,6 +8,10 @@ parser = argparse.ArgumentParser(description="Description")
  
 # add arguments to the parser
 parser.add_argument("-f", "--file")
+parser.add_argument("mode",
+                    help="display the square of a given number",
+                    nargs='?', default="total",
+                    choices=["total"])
 
 args = parser.parse_args()
 
@@ -16,14 +20,15 @@ if args.file:
 else:
     time_file = open('time.txt','r')
 
-total_time = timedelta()
+if args.mode == "total":
+    total_time = timedelta()
 
-for line in time_file:
-    date_time_description = line.split(" ", 2)
-    
-    hours, minutes = date_time_description[1].split(':', 1)
-    delta = timedelta(hours=int(hours), minutes=int(minutes))
-    
-    total_time += delta
+    for line in time_file:
+        date_time_description = line.split(" ", 2)
+        
+        hours, minutes = date_time_description[1].split(':', 1)
+        delta = timedelta(hours=int(hours), minutes=int(minutes))
+        
+        total_time += delta
 
-print('Total time: ', total_time)
+    print('Total time: ', total_time)