Find a function `FUN`

that leads to the following output:

`FUN(pi) - FUN(exp(1))`

`## [1] 1`

**Hint:** aim to keep the answer simple. The main logic of the function can often be summarized in a single line of R code.

##
**Answer: click to reveal**

We can write the function as follows:

```
FUN <- function(x) {
return(floor(x))
}
```

The R function `floor`

returns the largest integer not greater than the input argument:

` pi`

` ## [1] 3.141593`

` FUN(pi)`

` ## [1] 3`

` exp(1)`

` ## [1] 2.718282`

` FUN(exp(1))`

` ## [1] 2`

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