How many people do you need in a room in order to guarantee that there's a group of three people, each of whom has the same initials (first and last name only)?

Question

How many people do you need in a room in order to guarantee that there's a group of three people, each of whom has the same initials (first and last name only)?

676
677
1352
1353

I know that there are 26 letters of the alphabet. If I multiply 26 x 2 = 52
and then 52 x 26 = 1352.
But is that the minimum number necessary?

Answer 1

676*2=1352 is the maximum number of people that have NOT more than 2 identical initials.

So the correct answer is....