Q47

In a $\mathrm{B}^{+}$- tree where each node can hold at most four key values, a root to leaf path consists of the following nodes:

$$\mathrm{A}=(49,77,83,-), \mathrm{B}=(7,19,33,44), \mathrm{C}=\left(20^{*}, 22^{*}, 25^{*}, 26^{*}\right)$$

The $*$-marked keys signify that these are data entries in a leaf. Assume that a pointer between keys $k_{1}$ and $k_{2}$ points to a subtree containing keys in $\left[k_{1}, k_{2}\right)$, and that when a leaf is created, the smallest key in it is copied up into its parent. A record with key value $23$ is inserted into the $\mathrm{B}^{+}$- tree. The smallest key value in the parent of the leaf that contains $25^{*}$ is __________. (Answer in integer)