I actually did the math wrong, it's over 250 people. I'm also rounding a bit.
So, the population of Norway is about 5 million. I'm assuming that the number of people that they know is the same as the number of people that they know know, if you get what I mean. This means that, in order to find that number, we do this:
sqrt(5000000/77)=~254
Still an absurdly large number of people to know.