How many days does mars have in one year?

A Martian year is equal to 1.8809 Earth years (686.971 days), or 1 year, 320 days, and 18.2 hours 12 seconds

If you use the Martian day (about 2.7% longer than an Earth Day) for your calculation, a Martian year is equal to 668.5991 sols. That means that Mars rotates a little more than 668 times for every revolution around the Sun.