Ran is your neighbor and close friend. The distance between your two houses is only about 5 meters. He's in the same college as you, but he majored in mechanical engineering. Tonight, you see him calling with his girlfriend through your window. He looks like he's explaining something. Ran is still on the phone, then he looks at you. He takes a piece of paper and writes something, showing it to you through the window. "I'm stressed." Ran still holds the paper while calling with his girlfriend.