{-------------------------------
 Vichislit drobnuju chast 
  srednego geometri4eskogo 3x
   zadannih polojitelnih chisel.
 -------------------------------
  # Max Tkachenko # Group 112 # 
 -------------------------------
}

Program task_3_28___V(input,output);

 var 
  a, b, c : real;
  res : real;

 begin

  readln(a,b,c);

   res := exp( ln(a * b * c) / 3 );

  writeln(res);

 end.