How to properly block a network of ip addresses?

Question

Debian

Tell me how to properly block the ip network, otherwise I'm afraid to cheat) The
server receives a lot of requests from IP addresses
40.77.*.*
All of them have identical only the first four digits
How to block them through iptables with one rule?

Answer 1

iptables -I INPUT -s 44.77.0.0/16 -j DROP