how di i use PV=nRT for: How many moles of oxygen gas (O2) are in 448L at STP (273K and 1 atm of pressure)?

need help!

PV = nRT

P = 1 atmosphere
V = 448 L (that sounds high, perhaps it is 4.48 L or sometime similar.)
n = what you solve for.
R = universal gas constant = 0.08206 L*atm/mol*K
T = 273 K.