differential equations – From SSP = {x-> 0, y-> 1} how to obtain SSP1 = {0,1}?

My question is the following:

g = -Sqrt[1 - y^2]; h = Sqrt[1 - x^2]; Vars = {x, y};

ssp1 = solve[{g == 0, h == 0}, Vars]

I understood

$ { {x to -1, y to -1 }, {x to -1, y to 1 }, {x to 1, y to -1 }, {x to 1, y to 1 } } $

My question is how, from that, get SSP = {{- 1, -1}, {- 1,1}, {1, -1}, {1,1}}?

I need this to modify my program PLOTING DOMAIN OF DIFFERENTIAL EQUATIONS.