At 298 K the limiting molar conductivities, in $\text{S cm}^2\ \text{mol}^{-1}$, are $149.7$ for $\text{NH}_4\text{Cl}$, $247.8$ for NaOH and $126.5$ for NaCl. What is $\Lambda_m^\circ$ of $\text{NH}_4\text{OH}$?