The function takes a string as input and outputs the length of the string in words.

[CODE]:
```python
def f(x):
    # Split the input string by whitespaces to get individual words
    words = x.split()
    
    # Return the length of the list of words as the output
    return len(words)
```

The function splits the input string into words using whitespaces as separators. It then counts the number of words and returns the count as the output. This description captures the behavior of the function observed in the experiments.