Manufacturing - Calculate the OEE/Shift

Hi friends

Can you pl suggest me.

In machining section say for example in turning center

How to calculate the OEE/shift if the set up change is more than one and cycle time or no of piece/minute is different.

For example..

In shift A.

Part No A cycle time is 75seconds

Part No B cycle time is 70 Seconds

Part No C cycle time is 95second

Part No D cycle time is 100seconds.

Shift length is 8 hours.

Planned break hours:60min

Down time;80min(Including 4 setup change)

Part No A produced:50 pieces

Part No B produeced:75pieces

Part No C produced:56 pieces

Part No D produed:54 pieces.

In Above example can you pl calculate the OEE.

If you give the brief explanation with example which will be helpful for me.