diff --git a/foliator.py b/foliator.py
index 17e0132..eca5949 100755
--- a/foliator.py
+++ b/foliator.py
@@ -34,6 +34,30 @@ def append_folio_A6(input_pdf, offset, size, append_to):
         dpage.merge_page(ipage)
     return writer
 
+# Tries to find a partition as
+# num_sheets = max_folio_size * a + (max_folio_size - k) * b
+# where k is minimal. We let n = max_folio_size and L = num_sheets.
+# Note that when L > n^2, then k = 1 must succeed.
+def find_partition(num_sheets, max_folio_size):
+    max_a = num_sheets // max_folio_size
+    for k in range(1, max_folio_size):
+        # We want to solve a*k = L (mod n-k). This happens iff
+        # a*k' = L' (mod m') where k,L,m are divided by their gcd.
+        # Then, if k' and m' have a common factor, L' doesn't have it and there
+        # are no solutions. Otherwise, there's one solution mod m'.
+        g = math.gcd(max_folio_size - k, k, num_sheets)
+        mprime = (max_folio_size - k)//g
+        kprime = k//g
+        Lprime = num_sheets//g
+        if (math.gcd(kprime, mprime) > 1):
+            continue
+        a_mod_mprime = (pow(kprime, -1, mprime) * Lprime) % mprime
+        tosub = (max_a - a_mod_mprime + mprime) % mprime
+        # If we're a bit above, substract only a little. But a bit below implies
+        # substracting almost mprime.
+        candidate = max_a - tosub
+        if (candidate >= 0):
+            return (candidate, k)
 
 # Interprets input_pdf as a list of A6 pages, and appends to append_to with
 # A5 pages using the following rules: