Stranger Danger

For this challenge, the input will be a (long) string.

A word encountered for the first time is a stranger. A word encountered thrice becomes an acquaintance. A word encountered 5 times becomes a friend.

Create a function that takes the string and returns a list of two lists. The first is a list of acquaintances in the order they became an acquaintance (see example). The second is a list of friends in the order they became a friend. Words on the friend list should no longer be on the acquaintance list.

Examples

no_strangers("See Spot run. See Spot jump. Spot likes jumping. See Spot fly.")
➞ [["spot", "see"], []]
# "see" was encountered first, but "spot" became an acquaintance earlier.

Notes

• All words should be in lowercase.
• Punctuation should be stripped except for apostrophes (e.g. doesn't, aren't, etc).