I want to count rows in my dataset if 3 columns A-B-C match each other. I want to enter the value in a new column D. Here is an example. Thank you for your assistance!
| Column A | Column B | Column C | Column D |
| 7 | Z | S | 4 |
| 7 | Z | S | 4 |
| 1 | A | P | 3 |
| 1 | A | P | 3 |
| 1 | A | P | 3 |
| 7 | Z | S | 4 |
| 5 | E | M | 2 |
| 5 | E | M | 2 |
| 7 | Z | S | 4 |
