Subtraction goes down, not up. Silly me.

Spigot-API-Patches/0118-ItemStack-API-additions-for-quantity-flags-lore.patch

@@ -1,11 +1,11 @@
-From 79f36b1b98d9b888c633ef39dc73b532c89691b9 Mon Sep 17 00:00:00 2001
+From 503daef70a79ca4ea4f0583e6442c17aa74a94ee Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Fri, 22 Jun 2018 22:59:18 -0400
 Subject: [PATCH] ItemStack API additions for quantity/flags/lore
 
 
 diff --git a/src/main/java/org/bukkit/inventory/ItemStack.java b/src/main/java/org/bukkit/inventory/ItemStack.java
-index 82240129..bfd6307f 100644
+index 82240129..574cdf3b 100644
 --- a/src/main/java/org/bukkit/inventory/ItemStack.java
 +++ b/src/main/java/org/bukkit/inventory/ItemStack.java
 @@ -2,7 +2,9 @@ package org.bukkit.inventory;
@@ -85,7 +85,7 @@ index 82240129..bfd6307f 100644
 +     * @return The same item (not a clone)
 +     */
 +    public ItemStack subtract(int qty) {
-+        setAmount(Math.max(0, getAmount() + qty));
++        setAmount(Math.max(0, getAmount() - qty));
 +        return this;
 +    }
 +
@@ -162,5 +162,5 @@ index 82240129..bfd6307f 100644
      // Paper end
  }
 -- 
-2.17.1
+2.18.0