Consider the entries shown below in the forwarding table of an $\text{IP}$ router. Each entry consists of an $\text{IP}$ prefix and the corresponding next hop router for packets whose destination $\text{IP}$ address matches the prefix. The notation " /$\mathrm{N}$ " in a prefix indicates a subnet mask with the most significant $\mathrm{N}$ bits set to $1$.
Prefix | Next hop router |
$10.1 .1 .0 / 24$ | $\mathrm{R} 1$ |
$10.1 .1 .128 / 25$ | $\mathrm{R} 2$ |
$10.1 .1 .64 / 26$ | $\mathrm{R} 3$ |
$10.1 .1 .192 / 26$ | $\mathrm{R} 4$ |
This router forwards $20$ packets each to $5$ hosts. The $\text{IP}$ addresses of the hosts are $10.1.1.16, 10.1.1.72, 10.1.1.132, 10.1.1.191,$ and $10.1.1.205$. The number of packets forwarded via the next hop router $\mathrm{R} 2$ is __________.