\[ \boxed { \left ( \left ( y \left ( x \right ) \right ) ^{2}+1 \right ) {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) + \left ( 1-2\,y \left ( x \right ) \right ) \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{2}=0} \]
Mathematica: cpu = 0.085011 (sec), leaf count = 19 \[ \left \{\left \{y(x)\to \tan \left (\log \left (-c_1 \left (-c_2-x\right )\right )\right )\right \}\right \} \]
Maple: cpu = 1.528 (sec), leaf count = 11 \[ \left \{ y \left ( x \right ) =\tan \left ( \ln \left ( {\it \_C1}\,x+{ \it \_C2} \right ) \right ) \right \} \]