Suppose the functions $A$ and $B$ can be computed in $6$ and $4$ nanoseconds by functional units $U_A$ and $U_B$, respectively. Given two instances of $U_A$ and three instances of $U_B$, it is required to implement the computation $A(B(X_i))$ for $1\leq i \leq 100$. Ignoring all other delays, the minimum time required to complete this computation (in nanoseconds) is _______