diff --git a/judgels-backends/judgels-grader-engines/src/main/java/judgels/gabriel/engines/BlackboxGradingEngine.java b/judgels-backends/judgels-grader-engines/src/main/java/judgels/gabriel/engines/BlackboxGradingEngine.java
index 164fa24b7..2eb896811 100644
--- a/judgels-backends/judgels-grader-engines/src/main/java/judgels/gabriel/engines/BlackboxGradingEngine.java
+++ b/judgels-backends/judgels-grader-engines/src/main/java/judgels/gabriel/engines/BlackboxGradingEngine.java
@@ -335,7 +335,7 @@ private GradingResult buildResult() throws GradingException {
 
         return new GradingResult.Builder()
                 .verdict(gradingVerdict.getVerdict())
-                .score((int) Math.round(gradingVerdict.getPoints()))
+                .score((int) Math.floor(gradingVerdict.getPoints()))
                 .details(detailsString)
                 .build();
     }