diff --git a/mail_parser.py b/mail_parser.py
index 7c0b481..535c094 100644
--- a/mail_parser.py
+++ b/mail_parser.py
@@ -159,7 +159,7 @@ def main():
 
     for num in unread_emails:
         status, data = mail.fetch(num, "(RFC822)")
-        mail.store(num, '-FLAGS', '\Seen')
+        mail.store(num, '+FLAGS', '\\Seen')
         if status != "OK":
             print(f"Failed to fetch email ID {num}.")
             continue