The approximate angular resolution for human eye is $\varphi =5.08\times {10}^{-4}$ rad and typical photo printer prints a minimum of 360 dpi (dots per inch , 1 inch =2.54 cm) when the printed page is held at a minimum distance of $\alpha cm$ then one can not see the individual dots. Write the value of $\left[\alpha \right],$ where [] is the greatest integer function