Complex sentence: On his graduation day, she tried to give him a love letter that wished him good luck at the Life Count Administration Bureau however she was unable to because of a swarm of girls who also wanted to give him gifts.
Split into simpler sentences: On his graduation day, she tried to give him a love letter that wished him good luck at the Life Count Administration Bureau. However, she was unable to because of a swarm of girls who also wanted to give him gifts.