\[ \boxed { x{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) - \left ( y \left ( x \right ) \right ) ^{2}+1=0} \]
Mathematica: cpu = 0.022003 (sec), leaf count = 33 \[ \left \{\left \{y(x)\to \frac {1-e^{2 c_1} x^2}{e^{2 c_1} x^2+1}\right \}\right \} \]
Maple: cpu = 0.031 (sec), leaf count = 11 \[ \left \{ y \left ( x \right ) =-\tanh \left ( \ln \left ( x \right ) +{ \it \_C1} \right ) \right \} \]