Var
 a,b,c,p,S:Real;

Function Bo(x1,x2,x3:real):boolean;
begin
 Bo:=(x1>0) and (x2>0) and (x3>0)
    and ((x1+x2)>x3) and ((x1+x3)>x2) and ((x2+x3)>x1);
end;

Begin
 Repeat
  Write('a= ');
  Readln(a);
  Write('b= ');
  Readln(b);
  Write('c= ');
  Readln(c);
  If Not(Bo(a,b,c)) then Writeln('Improper set of parameters!');
 Until Bo(a,b,c);
 p:=(a+b+c)/2;
 S:=Sqrt(p*(p-a)*(p-b)*(p-c));
 Writeln('Ha= ',S*2/a:0:3);
 Writeln('Hb= ',S*2/b:0:3);
 Writeln('Hc= ',S*2/c:0:3);
 Readln
End.