diff --git a/Programs/P40_CipherText.py b/Programs/P40_CipherText.py
index 3733f43..e092f31 100644
--- a/Programs/P40_CipherText.py
+++ b/Programs/P40_CipherText.py
@@ -11,7 +11,10 @@ def encrypt(message, key):
         if chars in LETTERS:
             num = LETTERS.find(chars)
             num += key
-            encrypted +=  LETTERS[num]
+            if num>25:
+                num=num%25
+                num=num-1
+            encrypted =encrypted + LETTERS[num]
 
     return encrypted
 
@@ -21,8 +24,11 @@ def decrypt(message, key):
     for chars in message:
         if chars in LETTERS:
             num = LETTERS.find(chars)
-            num -= key
-            decrypted +=  LETTERS[num]
+            if num>25:
+                num=num%25
+                num=num-1
+            num = num -key
+            decrypted =decrypted+LETTERS[num]
 
     return decrypted