diff --git a/.vscode/settings.json b/.vscode/settings.json
index 5f1bbc6..984f7d5 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -116,5 +116,8 @@
   "markdown.extension.toc.updateOnSave": false,
   "python.testing.unittestArgs": ["-v", "-s", ".", "-p", "test_*.py"],
   "python.testing.pytestEnabled": false,
-  "python.testing.unittestEnabled": true
+  "python.testing.unittestEnabled": true,
+  "githubPullRequests.ignoredPullRequestBranches": [
+    "main"
+  ]
 }
diff --git a/challenges/challenge1.py b/challenges/challenge1.py
index 182c032..1b995b5 100644
--- a/challenges/challenge1.py
+++ b/challenges/challenge1.py
@@ -26,3 +26,14 @@
 Interpret what the final expression means in the context of allowing or blocking a login attempt.
 
 """
+not(A and(B or not B))
+not (A and True)
+not A
+
+The login credentials are not correct. The login attempt is blocked.
+
+#Oleksandr Maksymikhin
+#Momtaz Yaqubi
+#Rafaa Ali
+#Derek Karungani
+#Myint Myat
diff --git a/challenges/challenge2.py b/challenges/challenge2.py
index 504b52b..27282b5 100644
--- a/challenges/challenge2.py
+++ b/challenges/challenge2.py
@@ -29,3 +29,34 @@
 # -*- coding: utf-8 -*-
 
 """
+at_least_one = finance_access.union(tech_access).union(all_access)
+both_fincance_tech = finance_access.intersection(tech_access)
+exclusive = (finance_access.intersection(tech_access))
+
+#lack access
+lack_access = []
+for i in All_employees:
+    has_access = False
+    for j in at_least_one:
+        if i == j :
+            has_access = True
+    if has_access == False:
+        lack_access.append(i)
+        
+print (lack_access)
+
+overlap = both_fincance_tech
+
+    """
+    _Recommendation
+    We recommend do add one more group that include 
+    employeeID who have access to both finance and tech 
+    data to manage this group separately_
+    """
+
+
+#Oleksandr Maksymikhin
+#Momtaz Yaqubi
+#Rafaa Ali
+#Derek Karungani
+#Myint Myat
diff --git a/challenges/challenge3.py b/challenges/challenge3.py
index d20302e..41c5f3d 100644
--- a/challenges/challenge3.py
+++ b/challenges/challenge3.py
@@ -20,3 +20,8 @@
 Are there risks? Indicate employees who might be exposed to unnecessary data.
 Your output should visually highlight these relationships without explicitly listing them in a simple table or list. Think beyond just printing data—use a format that helps detect patterns at a glance.
 """
+from matplotlib_venn import venn2
+import matplotlib.pyplot as plt
+
+venn2([finance_access,tech_access], set_labels =('Finace','Tech'))
+plt.show()
diff --git a/challenges/challenge4.py b/challenges/challenge4.py
index e3638b3..9b34033 100644
--- a/challenges/challenge4.py
+++ b/challenges/challenge4.py
@@ -32,3 +32,27 @@
 Optionally convert the result back to binary with bin(), but focus on the XOR operation itself.
 
 """
+#Oleksandr Maksymikhin
+#Myint Myat
+#Rafaa Ali
+#Derek Karungani
+
+data_for_transmission_string = '1010101'
+data_for_transmission = int(data_for_transmission_string,2)
+security_key = int("1100110",2)
+checksum = data_for_transmission ^ security_key
+checksum_for_transmission = bin(checksum)
+
+
+
+def receiver_verify_data(data_for_transmission_string,checksum_for_transmission):
+    data_after_transmission = int(data_for_transmission_string,2)
+    receiver_checksum = data_after_transmission ^ security_key
+    
+    if receiver_checksum == checksum_for_transmission:
+        return "Transmission is successful"
+    else:
+        return "Transmission failed"
+      
+receiver_verify_data(data_for_transmission_string,checksum_for_transmission)
+      
\ No newline at end of file