Two cells of emfs 1 V and 2 V and internal resistance 2 $$\Omega$$ and 1 $$\Omega$$, respectively connected in parallel, gave a current of 1 A through an external resistance. If the polarity of one cell is reversed, then value of current through the external resistance will be $$\dfrac{\alpha}{5}$$ A. The value of $$\alpha$$ is __________.