How to convert this for loop to parfor loop?

Hello All, I am very new to parallel computing, and I am having hard time converting all my for loops to parfor loops. However, If I understood how to convert this part, I think I will be able to convert many parts of my code. Any help will be appreciated.

I = size(A,1);
J = size(B,2);
parfor i = 1:I
    for j = 1:J
        C(i,6*j - 5) = U(6*B(i,j) - 5,1);
        C(i,6*j - 4) = U(6*B(i,j) - 4,1);
        C(i,6*j - 3) = U(6*B(i,j) - 3,1);
        C(i,6*j - 2) = U(6*B(i,j) - 2,1);
        C(i,6*j - 1) = U(6*B(i,j) - 1,1);
        C(i,6*j - 0) = U(6*B(i,j) - 0,1);
    end
end