least squares solution to linear system

Dear all
I am having a linear system of the form
A*X=B and I want to find the X by using least squares.
For example my A is of dimension [205,3] and my B is of dimension[205,1]

 I am looking for the X matrix which is of the size [3,1]. In the matlab I was doing that by the function


 X = LSCOV(A,B) returns the ordinary least squares solution to the
    linear system of equations A*X = B, i.e., X is the N-by-1 vector that
    minimizes the sum of squared errors (B - A*X)'*(B - A*X), where A is
    M-by-N, and B is M-by-1


for example for the matrices

A =

     1     2     3
     4     5     6
     7     8     9

K>> B=[1 2 3]

B =

     1     2     3

lscov(A,B')

ans =

   -0.0000
         0
    0.3333

How I can get the same in R? I know about the lm function but it looks complicated to me how to insert formula and how to get exactly back only what I need