diff --git a/demo/demo.py b/demo/demo.py
index c5f0684..5bf6a4f 100644
--- a/demo/demo.py
+++ b/demo/demo.py
@@ -14,8 +14,8 @@ ret = _judger.run(max_cpu_time=1000,
                   # five args above can be _judger.UNLIMITED
                   exe_path="main",
                   input_path="1.in",
-                  output_path="/dev/stdout",
-                  error_path="/dev/stderr",
+                  output_path="1.out",
+                  error_path="1.out",
                   args=[],
                   # can be empty list
                   env=[],