diff --git a/src/ADNLPProblems/hs231.jl b/src/ADNLPProblems/hs231.jl
index 11a96d97..384b4202 100644
--- a/src/ADNLPProblems/hs231.jl
+++ b/src/ADNLPProblems/hs231.jl
@@ -6,7 +6,8 @@ function hs231(; n::Int = default_nvar, type::Val{T} = Val(Float64), kwargs...)
   end
   x0 = T[-1.2, 1]
   A = T[
-    1//3 1-1 // 3 1
+    1 // 3 1;
+    -1 // 3 1
   ]
   lcon = T[-0.1; -0.1]
   ucon = T[Inf; Inf]