diff --git a/nsysu_selector_helper/src/App.tsx b/nsysu_selector_helper/src/App.tsx
index efb4f30..1ad76d3 100644
--- a/nsysu_selector_helper/src/App.tsx
+++ b/nsysu_selector_helper/src/App.tsx
@@ -86,7 +86,7 @@ const App: FC = () => {
           dataSource={courses}
           renderItem={course => (
             <List.Item>
-              <Typography.Text>{course.name}</Typography.Text> - {course.teacher} ({course.credit} credits)
+              <Typography.Text>{course.id} {course.name}</Typography.Text> - {course.teacher} ({course.credit} credits)
             </List.Item>
           )}
           style={{ marginTop: '20px' }}
diff --git a/nsysu_selector_helper/src/api/NSYSUCourseAPI.ts b/nsysu_selector_helper/src/api/NSYSUCourseAPI.ts
index c7adaa8..22633ca 100644
--- a/nsysu_selector_helper/src/api/NSYSUCourseAPI.ts
+++ b/nsysu_selector_helper/src/api/NSYSUCourseAPI.ts
@@ -24,7 +24,11 @@ export class NSYSUCourseAPI {
     if (!response.ok) {
       throw new Error('Failed to fetch courses');
     }
-    return response.json();
+
+    return response.json().then((courses: Course[]) => {
+      return Array.from(new Set(courses.map(course => course.id)))
+        .map(id => courses.find(course => course.id === id)!);
+    });
   }
 
   static async getLatestCourses(): Promise<Course[]> {