Hitting hard

A thin, heavy metal plate is being bombarded by perpendicular beams of gas particles from both sides, as shown in the figure. The solid dots represent the molecules hitting from the left side and the faint dots represent the molecules hitting from the right side. The masses of these gas particles are each $m={ 10 }^{ -26 }\text{ kg}$ and the velocity before hitting is ${ v }_{ 0 }=5\text{ m/s}.$ The volume density of the gas particles on both sides is $n={ 10 }^{ 25 }\text{/m}^{ 3 }.$ Each beam has an area of $A=1\text{ m}^{ 2 }$ and the collisions are perfectly elastic.

What is the external force $F$ (in Newtons) required to move the plate with a constant velocity of $v=2\text{ m/s}?$