'Returns the number of integers moved by a permutation.
Examples
>>> from sympy.combinatorics import Permutation
>>> Permutation([0, 3, 2, 1]).length()
2
>>> Permutation([[0, 1], [2, 3]]).length()
4
See Also
min, max, support, cardinality, order, rank, size'

def length(self):

    return len(self.support())
