>>> from finances import inversio

>>> inversio(3000,6,10000,6,5)
0
>>> inversio(30000,7,10000,6,5)
41
>>> inversio(30000,10,10000,6,5)
1289

>>> inversio(120000,4.8,120000,4.6,20)
18
>>> inversio(120000,4.8,120000,4.5,20)
99
>>> inversio(190000,4.8,120000,4.6,20)
5458