HostA has established a TCP connection with HostB in a remote network. HostA is sending packets to HostB. Assume we have configured TCP$,$ somehow, to ACK every segment $($no ACKing every other segment$).$ Assume that the timeout is the same for all packets. HostB$$s $$window size$$ is $20000$ bytes. HostB has already received and acknowledged everything sent by HostA$$s application up to and including byte #$2,150.$ HostA now sends segments of the same application data stream in order:

P: $267$ bytes

Q: $127$ bytes

R: $361$ bytes

Suppose segments P$,$ Q$,$ and R arrive at Host B in order. What is the acknowledgment number on the segment sent in response to segment P$?$