N이/가 아닌 N
Use this pattern to say that something is not one thing, but another. It is useful when correcting an identity or making a contrast. Put the expected noun before 아닌, then the real noun after it. Example: "그 전화는 엄마가 아닌 친구에게서 온 전화였다." This means the call was not from her mother, but from a friend.
그 전화는 엄마가 아닌 친구에게서 온 전화였다.
The call was not from her mother, but from a friend.
