diff --git a/src/main.lua b/src/main.lua
index 3fbb3c0..9d14925 100644
--- a/src/main.lua
+++ b/src/main.lua
@@ -894,7 +894,7 @@ while true do
             local even = (VP_lengthofdict(stacks["stacks"])%(#accepted+1)) == 0
             if even then even = #accepted+1 else even = #accepted end
             stacks = VP_splitstack(stacks, even)
-            if #stacks["stacks"] ~= #accepted+1 then
+            if #stacks["stacks"] ~= even then
                 printError("Internal error with VP_splitstack. It returned "..#stacks["stacks"].." stacks.")
                 return
             end