Because users read top-down lists, they look at #1, #2, #3—but they often skip these because they already know the song. Research shows users hover on #7. It is the first "unknown" hit. If a song lives at #7, it gets the "curious click." If it jumps to #4, it gets the "validation click." Returning to #7 resets the curiosity loop.

The greatest Hot 100 song of all time (by points) frequently danced around the 7.4.7 zone. After its initial reign, "Blinding Lights" fell to #7, rebounded to #4 during the Super Bowl halftime show, and then stabilized at #7 again for six non-consecutive weeks.

: Print a message confirming who was replaced or explaining why the musician could not be added. Solution Code Structure