Odd. According to this venn diagram, that would only give you 3 additional characters of Greek from what you would already know coming form English.
https://commons.wikimedia.org/wiki/File:Venn_diagram_showing...
https://commons.wikimedia.org/wiki/File:Venn_diagram_showing...
If you grew up in Christian family, you know the Greek letters Χ (chi), Ρ (rho):
> https://en.wikipedia.org/wiki/Chi_Rho
P.S. I am aware that "Windows XP" jokes that arise from this Chi Rho symbol are very easy to write ...