{ HEX.PAS                   Copyright (c) TrSek alias Zdeno Sekerak }
{ Convert hex prezentation as string to long.                       }
{                                                                   }
{ Datum:13.07.2013                             http://www.trsek.com }

program HexConvert;

var
 a: longint;
 cislo: string;

{ Convert hex prezentation as string to long }
function HexToDec(S: string): Longint;
var I : Integer;
    Result : Longint;
begin
  Result := 0;
  for I := 1 to Length(S) do
  begin
   Result := 16*Result;
   if (S[I] >= '0') and (S[I] <= '9') then
       Result := Result + Ord(S[I]) - Ord('0')
   else if (S[I] >= 'A') and (S[I] <= 'F') then
       Result := Result + Ord(S[I]) - Ord('A') + 10
   else if (S[I] >= 'a') and (S[I] <= 'f') then
       Result := Result + Ord(S[I]) - Ord('a') + 10
  end;

  HexToDec := Result;
end;

{ test it }
begin
  write('Write hex : ');
  readln(cislo);

  a:= HexToDec(cislo);
  WriteLn('Integer is : ', a);
  ReadLn;
end.