diff --git a/p2d/parse_polygon_package.py b/p2d/parse_polygon_package.py
index 850244d..af5dca2 100644
--- a/p2d/parse_polygon_package.py
+++ b/p2d/parse_polygon_package.py
@@ -4,6 +4,7 @@
 import pathlib
 import re
 import sys
+from filecmp import cmp
 import xml.etree.ElementTree
 
 from p2d._version import __version__
@@ -153,14 +154,16 @@ def pol_path(*path):
 
         input_format = testset.find('input-path-pattern').text
         output_format = testset.find('answer-path-pattern').text
-        # Fetch samples from statements directory (for custum input/output)
+        # Fetch samples from statements directory (for custum output)
         sample_input_format = input_format.replace('tests/', os.path.join('statements', 'english') + '/example.')
         sample_output_format = output_format.replace('tests/', os.path.join('statements', 'english') + '/example.')
 
         for test in testset.iter('test'):
+            if 'sample' in test.attrib and not cmp(pol_path(input_format % local_id), pol_path(sample_input_format % local_id)):
+                raise RuntimeError('Custom inputs are not supported.')  # Becase DomJudge evaluates the same sample inputs that are provided to contestants.
             t = {
                 'num': test_id,
-                'in': pol_path(sample_input_format % local_id) if 'sample' in test.attrib else pol_path(input_format % local_id),
+                'in': pol_path(input_format % local_id),
                 'out': pol_path(sample_output_format % local_id) if 'sample' in test.attrib else pol_path(output_format % local_id),
                 'is_sample': 'sample' in test.attrib
             }