I've attached a pictorial representation of the answer below for you.
The bearing of M from N is 217° and marked with blue.
The bearing of N from M is marked with green, and is equal to the alternate angle marked in green too.
Now, you will notice that the angle marked with red plus that marked with green is equal to 217.
Again, you will notice that the angle marked with red equals 180°.
That means, the angle marked with green is equal to the one marked with blue minus the one marked with red, and it's mathematically equal to;
217 - 180 = 37°
Therefore, the bearing of N from M is 37°