program Arr2;

{$APPTYPE CONSOLE}

uses
  SysUtils;

Type
   TArr = array of integer;

procedure GetBin(var Num, Digit: Integer);
begin
   Digit := Num mod 2;
   Num := Num div 2;
end;

function ReverseBin(Bin: TArr): TArr;
var
   Index, Len: Integer;
begin
   Len := Length(Bin);
   SetLength(Result, Len);
   for Index := (Len - 1) downto 0 do
      ReverseBin[Len - Index - 1] := Bin[Index];
end;

procedure Main();
const
   CMaxNatural = 2147483647;
   CMinNatural = 1;

var
   P, ArrSize, Num, Digit, Index: Integer;
   Bin: TArr;
   IsCorrect: Boolean;
begin
   Write('Please, enter natural number to ', CMaxNatural,' : ');
   IsCorrect := false;
   repeat
      try
         Readln(P);
         if (P < CMinNatural) then
            Write('It is not a number from ', CMinNatural,' to ', CMaxNatural,' , please, enter valid number : ')
         else
            IsCorrect := true;
      except
         Write('Invalid input ! Please, enter natural number to ', CMaxNatural,' : ');
      end;
   until IsCorrect;
   Digit := 0;
   Num := P;
   ArrSize := 1;
   repeat
      GetBin(Num, Digit);
      SetLength(Bin, ArrSize);
      Bin[ArrSize-1] := Digit;
      inc(ArrSize);
   until (Num = 1);
   if (P > CMinNatural) then
   begin
   ArrSize := Length(Bin);
   inc(ArrSize);
   SetLength(Bin, ArrSize);
   Bin[ArrSize-1] := 1;
   Bin := ReverseBin(Bin);
   end;

   Write(P,' in binary digit system equals : ');
   for Index := 0 to high(Bin) do
      Write(Bin[Index]);
   Readln;
end;

var
   IsContinue, IsCorrect: Boolean;
   Answer: Char;

begin
   Writeln('This program converts a natural number to binary digit system.');
   Main;
end.