No VAC in my server :(

[wlfg]

i dont think i have screen :S this is not my server.. i got it as a host and i have the ssh cuz the person who gave it to me did now want to install the server himself...
what is the command to know if i have screen or dont?
i typed "which screen" and i get " /usr/bin/which: no screen in (/usr/........................................)"