What is the initial concentration of Fe^3+ ions before any reaction with thiocyanate?

the solution is made up of 7.00 mL of 2.0 E-3 M iron (III) nitrate mixed with 2.00 mL of 2.0 E-3 M potium thiocyanate, 3.00 mL of 0.5 M nitric acid & 8.00 mL of distilled water for a total of 20.0 mL