Two Neutral Particle

Two neutral particle like identical metal balls each of radius $r$ and mass $m$ are connected by a light inextensible conducting thread of length $L$ . The balls are held in free space with separation between their centres $l$ . $(r<<l<L)$ . Now everywhere a uniform electric field directed along the line joining the centres of the balls is switched on and then the balls are released.
Find maximum speeds of the balls in subsequent motion.
Answer comes in the form of $\alpha \sqrt{\frac{\epsilon_{0}rE^{\beta}(L^{\gamma}-l^{\delta})}{m}}$

Type your answer as $\alpha+\beta+\gamma+\delta=?$