diff --git a/ubuntu18to20/upgrader.py b/ubuntu18to20/upgrader.py
index e12d7e0..4df8266 100644
--- a/ubuntu18to20/upgrader.py
+++ b/ubuntu18to20/upgrader.py
@@ -94,7 +94,7 @@ def construct_actions(
                     '\g<1>://\g<2>/\g<3>20.04\g<4>',
                 ),
                 actions.ReplaceAptReposRegexp(
-                    r'(http|https)://([^/]+)/(.*\b)18\(\b.*)',
+                    r'(http|https)://([^/]+)/(.*\b)18(\b.*)',
                     '\g<1>://\g<2>/\g<3>20\g<4>',
                 ),
             ],