Birdday Party 19-5 (or Birdday Party Cake 3 Level 5) is the 20th level in the Birdday Party and the 305th level (if you don't count the Facebook bonus levels) in Angry Birds overall.
Not much problem if you detonate the leftmost TNT.
Try to detonate the TNT on the right side with the Red bird, though this is not entirely necessary. If the right tower still stands, use a Pink bird to float it into oblivion. Otherwise, send a Pink bird straight ahead, lifting the left side of the structure and detonating the TNT there.