How to find the Cost Basis of the matching shares from my employer.

Through my employer I'm eligible to buy company shares every year via an empoyee stock plan.

My employer is giving back, for 2 shares purchased, 1 share free.

 

So for last year I received 291.686 free shares, and the day they are released/vested to me, they worth $1475.56. I can see this amount in my payslip and for this amount I paid $437.5 in taxes (federal/ss/medicare).

 

So this $1475.56 is the cost basis of 291.686 shares or I have to add as well the amount paid in taxes ie $437.5?