First card can be anyone of 52 cards..so 52 ways.
Second card can be anyone from 39 cards ( excluding the previously chosen suit)...so 39 ways
Third card can be anyone from 26 cards ( excluding previous 2 suits)...so 26 ways
Total = 52*39*26 ways = 24* 13^3 ways I am getting..
Where am I counting wrong ? Please explain