A for paper 

A4 paper is one of the most widely used standard paper sizes in the world. Measuring 210 × 297 mm (8.27 × 11.69 inches), it is commonly used for printing, photocopying, letters, reports, forms, schoolwork, and business documents.

Most important, you can consider me a beautiful A4 paper to write down what bothers you

A4 belongs to the ISO 216 international paper-size standard. Its practical proportions allow documents to be resized between different A-series formats while maintaining the same aspect ratio. Available in various weights, colors, finishes, and paper qualities, A4 paper is suitable for both everyday office use and professional printing.

Simple, versatile, and universally recognized, A4 paper remains an essential material in offices, schools, businesses, and homes around the world