diff --git a/latex/insertoverlay.py b/latex/insertoverlay.py
index d4f527c..6b421df 100644
--- a/latex/insertoverlay.py
+++ b/latex/insertoverlay.py
@@ -27,7 +27,7 @@ def do_file(fn, start=0) :
     xs = set.union(*[extract(l) for l in ls])
     # some integer overlays may not be referred to (especially 1), so we add them
     xs |= set(range(1, int(max(xs))))
-    newi = dict(zip(sorted(xs), range(len(xs)+1)[1:]))
+    newi = dict(zip(sorted(xs), range(1, len(xs)+1)))
     print(newi)
     for l in ls:
         sys.stdout.write(sub(l, newi))