\[ \boxed { y \left ( x \right ) \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{2}-1=0} \]
Mathematica: cpu = 0.014502 (sec), leaf count = 43 \[ \left \{\left \{y(x)\to \left (\frac {3}{2}\right )^{2/3} \left (c_1-x\right ){}^{2/3}\right \},\left \{y(x)\to \left (\frac {3}{2}\right )^{2/3} \left (c_1+x\right ){}^{2/3}\right \}\right \} \]
Maple: cpu = 0.577 (sec), leaf count = 27 \[ \left \{ x-{\frac {2}{3} \left ( y \left ( x \right ) \right ) ^{{\frac { 3}{2}}}}-{\it \_C1}=0,x+{\frac {2}{3} \left ( y \left ( x \right ) \right ) ^{{\frac {3}{2}}}}-{\it \_C1}=0 \right \} \]