If f(x), whose graph is shown below, is defined on 1 <= x <= 6, what is the maximum value of f^{-1}(x)?

If f(x), whose graph is shown below, is defined on 1 <= x <= 6, what is the maximum value of f^{-1}(x)?

edit: Please I really need help!!!

edit: Seriously can anyone help?

edit: never mind I solved it its 6