Importing Maya Animated Camera into Unreal Engine 4.16.1

Hi All,

I was trying to get an animated Maya camera into Unreal Engine but it always had mis-matching issues for transforms, mainly rotations. However after trying few different things for several times I finally ended up getting it right in Unreal Engine.
I had to input -90 value in rotation-x & rotation-y within CineCamera Actor.

Although it worked, i am not completely sure why it worked. Why I had to input -90 in both X & Y rotations for it to match just like in maya. I would like to know more on this.