diff --git a/AlgebraicDataflowArchitectureModel/models/InventoryManagement.model b/AlgebraicDataflowArchitectureModel/models/InventoryManagement.model
index 31bcdad..424e589 100644
--- a/AlgebraicDataflowArchitectureModel/models/InventoryManagement.model
+++ b/AlgebraicDataflowArchitectureModel/models/InventoryManagement.model
@@ -4,7 +4,7 @@
 }
 
 channel ReceivingOrShipping(itemId:Str) {
-	out inventory.{itemId}.count(prev_quantity:Int, receiveOrShip(quantity:Int)) = if(prev_quantity + quantity >= 0, 
+	out inventory.{itemId}.count(prev_quantity:Int, receiveOrShip(quantity:Int)) = if((prev_quantity + quantity) >= 0, 
 																						prev_quantity + quantity, 
 																						prev_quantity)
 }