A uniformly charged wire of linear charge density $\text{'}\lambda \text{'}$  coulomb/m is placed inside a cube of side length $\text{'}\ell \text{'}$  such that its maximum possible length is covered by the cube. Then the flux through the cube is $\varphi =\sqrt{n}\left(\frac{\lambda \ell }{{\in }_0}\right)$  where n is