diff --git a/all_good_ids.py b/all_good_ids.py
new file mode 100644
index 0000000..ddcca1f
--- /dev/null
+++ b/all_good_ids.py
@@ -0,0 +1,18 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*- 
+
+import sys
+import os
+from os.path import join
+
+all_ids = set()
+
+for dirpath, dirnames, filenames in os.walk(sys.argv[1]):
+    for f in filenames:
+        fp = os.path.join(dirpath, f)
+        for uid in open(fp):
+            all_ids.add(int(uid))
+
+f_out = open(sys.argv[2],'w')
+for uid in all_ids:
+    f_out.write(str(uid) + '\n')