Input capacitor of Boost converter

i am working with a boost converter(see picture attached please) and I have to design it in PSIM, i could to dimension the all components except the input capacitor, anybody can help me?

This capacitor does not impact the output characteristics or current control of the inductor current and would be used to help control conducted EMI from your input source. Sizing it is dependant on what sort of input specifications you are design with.

Thank you !