Gravitation

The masses and radii of the moon and the earth are \(\mathrm{M_1, R_1}\) and \(\mathrm{M_2, R_2}\) respectively. Their centres are at a distance \(\mathrm{d}\) apart. What should be the minimum speed with which a body of mass '\(m\)' should be projected from a point midway between their centres, so as to escape to infinity?