You will need 2 buttons.

Finished measurements:
Bust circumference: 38.75(42, 46.5, 50, 54.5)“ 96(107, 118, 127, 138) cm
Finished length: 29(30, 30.75, 31.5, 32.25)” 74(76, 78, 80, 82) cm
Sleeve to armhole: 17(18, 18, 18, 19)“ 43(46, 46, 48, 48) cm

Yarn used:
James C. Brett Marble Chunky
Shade MC92 - 3(3, 4, 4, 4) balls

For the complete shade range, please visit: https://www.jamescbrett.co.uk/yarn/marble-chunky