'Return the number of possible trees of this Prufer object.
Examples
>>> from sympy.combinatorics.prufer import Prufer
>>> Prufer([0]*4).size == Prufer([6]*4).size == 1296
True
See Also
prufer_rank, rank, next, prev'

@property
def size(self):

    return (self.prev(self.rank).prev().rank + 1)
