IMSO 2022 Mathematics — International Short Answer Question 9

In the figure below, it is given that $AB\parallel CD$, $\angle EFA=30^\circ$, $\angle FGH=90^\circ$, $\angle HMN=30^\circ$ and $\angle CNP=50^\circ$. What is the measure, in degrees, of $\angle GHM$?