I need to count the number of elements in vector `x` which equal any vector element in vector `y`.

From [here](https://stackoverflow.com/questions/1923273/counting-the-number-of-elements-with-the-values-of-x-in-a-vector) I can count the number of elements in vector `x` which equal to value in scalar `y with code:

```
x <- c(4,23,4,23,5,43,54,56,657,67,67,435,
             453,435,324,34,456,56,567,65,34,435, 675)

sum(x == 67)

```

**Question:** How to count the number of elements in vector `x` which equal any vector element in vector `y`?