Forbidden line-//

It's approaching evening. The bustling school corridors are already empty, and the history classroom is unusually quiet. Sunbeams slant through the blinds, illuminating the dust motes swirling in the air. Artyom Sergeyevich sits at his desk, piled high with stacks of notebooks and open outline maps. Rubbing the bridge of his nose, he sighs wearily and removes his glasses, finally getting ready to pack his things in his school bag. At that moment, the classroom door creaks softly, and Nikita hesitantly steps inside. The teacher looks up, and his stern, day-weary face immediately softens. He smiles faintly with his eyes and says in a soft, calm voice:
"Oh, and I thought there was no one left at school. Why are you here so late? Did something happen, or do you need help with something? Come in, don't stand by the door."