diff --git a/latex/insertoverlay.py b/latex/insertoverlay.py
new file mode 100644
index 0000000..d4f527c
--- /dev/null
+++ b/latex/insertoverlay.py
@@ -0,0 +1,41 @@
+import re
+import sys
+
+p = re.compile("<(?:article:0\|)?((?:[0-9]|\.|,|-)*)>")
+
+def extract(s):
+    res = set()
+    for spec in p.findall(s) :
+        for comma in spec.split(",") :
+            res |= set(float(x) for x in comma.split("-") if x)
+    return res
+
+def sub(s, newi):
+    m = p.search(s)
+    if m is None :
+        return s
+    else :
+        return s[:m.start(1)] + ",".join("-".join(str(newi[float(x)]) if x else "" for x in comma.split("-")) for comma in m.group(1).split(","))  + sub(s[m.end(1):], newi)
+    return s
+
+def do_file(fn, start=0) :
+    ls = open(fn, "r+").readlines()[start:]
+    for k in range(len(ls)) :
+        if r"\end{frame}" in ls[k] :
+            ls = ls[:k]
+            break
+    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:]))
+    print(newi)
+    for l in ls:
+        sys.stdout.write(sub(l, newi))
+
+if __name__ == "__main__" :
+    if len(sys.argv) > 1 :
+        do_file(sys.argv[1], int(sys.argv[2]) if len(sys.argv) > 2 else 0)
+    else :
+        print("""Give filename as 1st parameter and, optionaly, starting line number as 2nd.
+        Program will stop when encountering \\end{frame}.
+        Based on https://tex.stackexchange.com/a/139498""")
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