Just look at the hairstyle and skin color. Lee Si Hyun has perm hair and had a fair skin. The other one has a bit of tan and straight hair.
If you're reading fast it gets confusing. I had to pause and reread and scroll up and down and up and down to figure out who's who.
Just look at the hairstyle and skin color. Lee Si Hyun has perm hair and had a fair skin. The other one has a bit of tan and straight hair.