program Project1;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.SysUtils;

function Test(a,b,c: Double): Boolean;
begin
  b := b - a;
  c := c - a;

  if (b < 0.5) and (c < 0.5) then
    Exit(True);
  if (b > 0.5) and (c > 0.5) then
    Exit(True);

  Result := False;
end;

procedure t;
var
  i, j: Integer;
const
  N = 1000000;
begin
 // Randomize();
  j := 0;
  for i := 1 to N do begin
    if Test(Random(), Random(), Random())  then
      Inc(j);

  end;

  Writeln(100 * j/ N : 4:3 );
end;

begin
  try
    t;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.