Electron entering a capacitor

Problem:

An electron enters the region between the plates of a parallel plate capacitor at a point equidistant from either plate. The capacitor plates are $2* 10^{-2}$ m apart & $10^{-1}$ m long. A potential difference of 300 volt is kept across the plates. Assuming that the initial velocity of the electron is parallel to the capacitor plates, calculate the largest value of the velocity of the electron so that they do not fly out of the capacitor at the other end. [IIT JEE]