y=[tex] \left \{ {{ x^{2} } ,\atop { \sqrt{x} }}, ight {{x \leq 0} \atop {x>0}} ight. [/tex]  

var  x, y: real;begin  readln(x);  if (x <= 0) then    y := sqr(x)  else    y := sqrt(x);  writeln(y);end.