diff --git a/Concurrent Systems/notes/7- MUTEX-free concurrency.md b/Concurrent Systems/notes/7- MUTEX-free concurrency.md
index 94e32b2..ef4a638 100644
--- a/Concurrent Systems/notes/7- MUTEX-free concurrency.md	
+++ b/Concurrent Systems/notes/7- MUTEX-free concurrency.md	
@@ -121,7 +121,7 @@ push(v) :=
 pop() :=
 	k <- NEXT-1
 	for i = k down to 1
-	tmp <- REG[1].swap(⊥)
+	tmp <- REG[i].swap(⊥)
 	if tmp != ⊥ then
 		return tmp
 	return ⊥