diff --git a/contracts/SamWitchOrderBook.sol b/contracts/SamWitchOrderBook.sol
index 50f70aa..a4fd32b 100644
--- a/contracts/SamWitchOrderBook.sol
+++ b/contracts/SamWitchOrderBook.sol
@@ -797,7 +797,8 @@ contract SamWitchOrderBook is ISamWitchOrderBook, ERC1155Holder, UUPSUpgradeable
           tokenIdsClaimable[orderId][_tokenId] += quantityNFTClaimable;
 
           _orderIdsPool[numberOfOrders] = orderId;
-          _quantitiesPool[numberOfOrders++] = quantityNFTClaimable;
+          _quantitiesPool[numberOfOrders] = quantityNFTClaimable;
+          numberOfOrders = numberOfOrders.inc();
 
           if (numberOfOrders >= MAX_ORDERS_HIT) {
             revert TooManyOrdersHit();