Five equal resistor of each $R \Omega$ are connected as shown in the figures. calculate the equivalent resistance between A and B

Question

$\begin{array}{1 1} R \;\Omega \\7\;\Omega \\ 8.0 \times 10^{-7}\;\Omega \\ 3.0 \times 10^{-7}\;\Omega \;m\end{array} $