Floor square sum

Algebra Level 4

$S = \left\lfloor \sqrt{1} \right\rfloor +\left\lfloor \sqrt{2} \right\rfloor +\left\lfloor \sqrt{3} \right\rfloor +\cdots +\left\lfloor \sqrt{1988} \right\rfloor$

Find the value of $S$ .