It is known that the electric force of repulsion between two electrons is much stronger than the gravitational attraction. For two electrons at a distance d apart, calculate the ratio of the size of the electrostatic repulsion to that of the gravitational attraction. Use the following data: k = 8.99×109 Nm2/C2, e = 1.60×10-19 C, G = 6.67×10-11 Nm2/kg2, me = 9.11×10-31 kg.