I'm trying to figure out how to count an iterator item twice if some condition is met, but only once otherwise.

```
dbg!((1..=20).zip((1..=20).rev())
.filter(|(a,b)| a % 2 == 0 || b % 3 == 0)
.inspect(|ab| println!("{:?}", ab))
.count());
```

Yields a count of 13 for the items

```
(2, 19)
(3, 18)
(4, 17)
(6, 15)
(8, 13)
(9, 12)
(10, 11)
(12, 9)
(14, 7)
(15, 6)
(16, 5)
(18, 3)
(20, 1)
```

but I would like to be able to count the following tuples twice since both values satisfy the condition

```
(6, 15)
(12, 9)
(18, 3)
```

and end up with a count of 16. Any suggestions for how to accomplish this? I'm trying to avoid iterating separately and then adding the counts together.