Update app.py

app.py

@@ -36,13 +36,18 @@ def clean_latex(latex):
 
 # Fallback to external LLM microservice
 def request_llm_fallback(bad_latex, llm_url):
+    # Clean known junk before sending to LLM
+    pre_cleaned = re.sub(
+        r'(\\!?pm|\\not=?|\\!|\\L|\\perp|\\bar|\\Sigma|\\boldmath|G|L(?=\^))', '', bad_latex
+    )
     try:
-        response = requests.post(f"{llm_url}/clean", json={"prompt": bad_latex})
+        response = requests.post(f"{llm_url}/clean", json={"prompt": pre_cleaned})
         if response.status_code == 200:
-            return response.json().get("cleaned_latex", bad_latex)
+            return response.json().get("cleaned_latex", pre_cleaned)
     except Exception as e:
         print(f"LLM fallback failed: {e}")
-    return bad_latex
+    return pre_cleaned
+
 
 # Main function
 def solve_polynomial(image, llm_url):