\left.\begin{array}{l}\text { [ Properties of medians. Centroid of a triangle. ]} \\ {[\quad \text { Inscribed quadrilaterals (other). ] }}\end{array}\right]

Medians $A M$ and $B E$ of triangle $A B C$ intersect at point $O$. Points $O, M, E, C$ lie on the same circle. Find $A B$, if $B E = A M = 3$.