The contrasting colors

The colored pens came out of the pencil case and started dancing happily on the desk. Suddenly, they noticed a paper on the desk with a beautiful scene. But the beautiful drawing lacked the multiple colors. So the pens decided to color the drawing, excluding the black pen. However, they later realized that black is indispensable to draw the darkness of the night. So they returned and gathered all together again after apologizing to their friend, the black pen. Number of pages: 23 pages Size: 21.5*21.5 cm