Math Help - One more permutation problem

Sorry for bothering you guys again but here's another problem that I'm having difficulty with:

How many numbers can be formed using all of the digits 1, 2, 3, 4, 5, 6, and 7 if the odd digits must be in ascending order and the even digits in descending order?

Thanks for your time!

There are seven places, select four to place the odd digits.