Использование стандартных процедур и функций

uses crt;
var N:word;
begin
clrscr;
repeat
writeln('Vvedite chislo ot 1 do 1000');
readln(N);
until (N>0)and(N<=1000);
if N div 1000=1 then write('Odna tysycha') else
  begin
    case N div 100 of
    1:write('sto ');
    2:write('dvesti ');
    3:write('trista ');
    4:write('chetyresta ');
    5:write('pytsot ');
    6:write('shestsot ');
    7:write('semsot ');
    8:write('vosemsot ');
    9:write('devyatsot ');
    end;
    case N mod 100 div 10 of
    1:case  N mod 10 of
      0:write('desyat');
      1:write('odinadcat');
      2:write('dvenadcat');
      3:write('trinadcat');
      4:write('chetyrnadcat');
      5:write('pyatnadcat');
      6:write('shestnadcat');
      7:write('semnadcat');
      8:write('vosemnadcat');
      9:write('devyatnadcat');
      end;
    2:write('dvadcat ');
    3:write('tridcat ');
    4:write('sorok ');
    5:write('pytdesyat ');
    6:write('shestdesyat ');
    7:write('semdesyat ');
    8:write('vosemdesyat ');
    9:write('devyanosto ');
    end;
    if N mod 100 div 10 <>1 then
    case N mod 10 of
    1:write('odin');
    2:write('dva');
    3:write('tri');
    4:write('chetyre');
    5:write('pyat');
    6:write('shest');
    7:write('sem');
    8:write('vosem');
    9:write('devyt');
    end;
  end;
readln
end.