Ricci scalar for FRW metric with lapse function

I need the Ricci scalar for the FRW metric with a general lapse function $N$:
$$ds^2=-N^2(t) dt^2+a^2(t)left [frac{dr^2}{1-kr^2}+r^2(dtheta^2+sin^2theta dphi^2)right]$$
Could someone put this into Mathematica as I don’t have it?