diff --git a/dataset/bt_expansion/input.txt b/dataset/bt_expansion/input.txt
new file mode 100644
index 0000000..536fa42
--- /dev/null
+++ b/dataset/bt_expansion/input.txt
@@ -0,0 +1 @@
+{pre: 1, 2, 3}{action: moveTo(s)}{add: 4}{del: 2, 3}
\ No newline at end of file