program srgeom(output, input);
var  a,b,c,sr:real;
begin
   write('input a,b,c');
   read(a,b,c);
   sr:=exp(ln(a*b*c)/3);
   sr:=sr-trunc(sr);
   writeln('drobnaya chast''srednih geometricheskih etih chisel =',sr:1:5)
end.