It would be appreciated if someone can assist with a formula. I have two colums A1:A26 (Purchase order heading) and B1:B26 (Num of devices). I need to calculate the unique numbers (Purchase Order) related to the number of devices.

Purchase Order Number of Devices
4501140744 2.00
4501140744 2.00
4501140744 2.00
4501140744 2.00
4501140744 2.00
4501140744 2.00
4501140744 2.00
4501173972 2.00
4501174428 2.00
4501174429 2.00
4501174599 2.00
4501175052 2.00
4501174733 2.00
4501174739 2.00
4501174743 2.00
4501175522 2.00
4501140744 2.00
4501140744 3.00
4501175510 3.00
4501172458 3.00
4501172458 3.00
4501172458 3.00
4501172458 3.00
4501176472 3.00
4501176793 3.00