\[ \boxed { \left ( {x}^{2}+1 \right ) {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) + \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{2}+1=0} \]
Mathematica: cpu = 0.042005 (sec), leaf count = 33 \[ \left \{\left \{y(x)\to -x \cot \left (c_1\right )+\csc ^2\left (c_1\right ) \log \left (-x \sin \left (c_1\right )-\cos \left (c_1\right )\right )+c_2\right \}\right \} \]
Maple: cpu = 0.826 (sec), leaf count = 27 \[ \left \{ y \left ( x \right ) ={\frac {x}{{\it \_C1}}}+\ln \left ( x{ \it \_C1}-1 \right ) +{\frac {\ln \left ( x{\it \_C1}-1 \right ) }{{{ \it \_C1}}^{2}}}+{\it \_C2} \right \} \]