diff --git a/ciphers/rot13.py b/ciphers/rot13.py
index b367c3215..9a04c05df 100644
--- a/ciphers/rot13.py
+++ b/ciphers/rot13.py
@@ -1,14 +1,20 @@
-def dencrypt(s: str, n: int = 13) -> str:
+def apply_rot13(s: str) -> str:
     """
-    https://en.wikipedia.org/wiki/ROT13
+    Performs a special reversible case of the Caesar cipher.
+    Rotates a text by 13 letters.
+    Also see: https://en.wikipedia.org/wiki/ROT13
 
+    Example usage:
     >>> msg = "My secret bank account number is 173-52946 so don't tell anyone!!"
-    >>> s = dencrypt(msg)
+    >>> s = apply_rot13(msg)
     >>> s
     "Zl frperg onax nppbhag ahzore vf 173-52946 fb qba'g gryy nalbar!!"
-    >>> dencrypt(s) == msg
+    >>> apply_rot13(s) == msg
     True
     """
+    if not isinstance(s, str):
+        return "The input must be a string. Please try again."
+    n = 13
     out = ""
     for c in s:
         if "A" <= c <= "Z":
@@ -21,13 +27,13 @@ def dencrypt(s: str, n: int = 13) -> str:
 
 
 def main() -> None:
-    s0 = input("Enter message: ")
+    s0 = input("Enter message: ").strip()
 
-    s1 = dencrypt(s0, 13)
+    s1 = apply_rot13(s0)
     print("Encryption:", s1)
 
-    s2 = dencrypt(s1, 13)
-    print("Decryption: ", s2)
+    s2 = apply_rot13(s1)
+    print("Decryption:", s2)
 
 
 if __name__ == "__main__":