[Fwd: need some help]

Dear all,

I need some help.
I have some problems trying to use the packages for linear programming. 
I've loaded the packages to R but when I try to use the function R sends 
an error warning.
I don't know if  something is missing
This is what it shows

# Set up problem: maximize
# x1 + 9 x2 + x3 subject to
# x1 + 2 x2 + 3 x3 <= 9
# 3 x1 + 2 x2 + 2 x3 <= 15
#
f.obj <- c(1, 9, 3)
f.con <- matrix (c(1, 2, 3, 3, 2, 2), nrow=2, byrow=TRUE)
f.dir <- c("<=", "<=")
f.rhs <- c(9, 15)
lp ("max", f.obj, f.con, f.dir, f.rhs)

Error: couldn't find function "lp"

Thank you all
ARC