diff --git a/Kotlin/src/main/kotlin/com/gildedrose/GildedRose.kt b/Kotlin/src/main/kotlin/com/gildedrose/GildedRose.kt
index 49b7e99e..9645131f 100644
--- a/Kotlin/src/main/kotlin/com/gildedrose/GildedRose.kt
+++ b/Kotlin/src/main/kotlin/com/gildedrose/GildedRose.kt
@@ -59,7 +59,7 @@ class GildedRose(var items: List<Item>) {
 
     private fun downGradeQuality(i: Int) {
         if (items[i].quality > 0) {
-            items[i].quality =- 1
+            items[i].quality -= 1
         }
     }