You and your friends are planning on all hanging out! Everyone has different interests and ideas on what to do. Based on everyone’s list of ideas, find the most popular idea(s) so everyone will be happy.

Write a function that takes in a dictionary where:

• The keys are the names of your friends.
• The values are lists of activities each friend suggested.

The function should return a list of the activities that appear the most in the lists. If there is a tie for the most popular activity, return all activities that are tied.

friend_activities = {
    "Alice": ["movie", "hiking", "bowling"],
    "Bob": ["hiking", "movie", "swimming"],
    "Charlie": ["movie", "bowling", "tennis"]
}

# The activity "movie" appears 3 times, which is the most.
# "hiking" and "bowling" appear 2 times each.
# So, the function should return ["movie"] as it's the most popular.