diff --git a/buggy.py b/buggy.py
--- a/buggy.py
+++ b/buggy.py
@@ -97,7 +97,7 @@
             mx = mxColumns[y3 - M]
             if mx > a2:
                 a2 = mx
-            a3 = mxULss[N][y3]
+            a3 = mxURss[N][y3]
             area = a1 + a2 + a3
             #        print('# (x1, x3):', (x1, x3), '/ (a1, a2, a3):', (a1, a2, a3), '/ area:', area)
             if area > ans:
