diff --git a/files/check_dir_size_for_backup.py b/files/check_dir_size_for_backup.py
index 1810e18..522ea00 100644
--- a/files/check_dir_size_for_backup.py
+++ b/files/check_dir_size_for_backup.py
@@ -15,7 +15,7 @@ if __name__ == "__main__":
     args = parser.parse_args()
     
     # check parameter #
-    if not args.PATH.replace("/", "").isalnum():
+    if not args.PATH.replace("/", "").replace("-","").isalnum():
         print("Illegal Path: {} (must be alphanum + /)".format(args.PATH))
         sys.exit(1)
     elif not args.PATH.startswith("/"):