The melody of The Greatest by Sia runs 482 notes across 47 bars, 3:05 long in Fm at 96 beats per minute. The tab sits almost entirely in the first two frets, one note at a time — no chords to barre and no strumming pattern to keep up with. A piano backing track plays the chords and bass underneath, so the line you are learning sounds like the record even at half speed.
Prefer to strum and sing it instead? The Greatest chords and lyrics.