diff --git a/bc.py b/bc.py
index e3b1310..0c7b2b9 100644
--- a/bc.py
+++ b/bc.py
@@ -70,7 +70,11 @@ async def coin(context: Message) -> None:
         return
     else:
         prices = binanceclient.get_all_tickers()
-        number = float(action[0])
+        try:
+            number = float(action[0])
+        except ValueError:
+            await context.edit('输入错误.\n-bc 数量 币种1 币种2')
+            return
         _from = action[1].upper().strip()
         _to = action[2].upper().strip()
         front_text = ''
diff --git a/list.json b/list.json
index 8f1144d..9a9eff3 100644
--- a/list.json
+++ b/list.json
@@ -442,7 +442,7 @@
         },
         {
             "name": "bc",
-            "version": "1.21",
+            "version": "1.22",
             "section": "chat",
             "maintainer": "Pentacene",
             "size": "8.0 kb",