Good day

I have 2 points:

P1=
14191455994323772597241090149390194844060070267542625335030526433746129697775
56665880437360020920156314485129600171712953656147713075817973497803847118302

P2=
14191455994323772597241090149390194844060070267542625335030526433746129697775
59126208799956174503414670523558307681557031009492850963639610510104987553361

Both points have the same X, and different Y
One of this points is positive (x,y), and another is negative (x,-y)

If we add this points with each other we get zero.

So how to define which coordinate is negative and which is positive? Any solution? Advices? 

Thank you!