Neither first my program, nor second are right.
Why??!
Here they are:

program first;
const
   ks : set of char = ['>','<','a'..'z','A'..'Z','0'..'9',';',':','-
','!','?','.',',',' '];
var
  ch : char;
  pos : byte;
  res : string[80];
begin
  res:='';
  for pos:=1 to 80 do res:=res+' ';
  pos:=1;
  ch:=#0;
  while (ch<>#26) do
  begin
  read(ch);
  if ch=#26 then break;
  if not (ch in ks) then continue;

  if ch='>' then
   begin
    if pos=80 then pos:=1;
   end
  else
  if ch='<' then
   begin
    if pos<>1 then dec(pos);
   end
  else
  begin
   res[pos]:=ch;
   if pos=79 then pos:=1 else
   inc(pos);
  end

  end;
  Writeln(res);
end.

program second;
const
   ks : set of char = ['>','<','a'..'z','A'..'Z','0'..'9',';',':','-
','!','?','.',',',' '];
var
  ch : char;
  pos : byte;
  res : string[80];
begin
  res:='';
  for pos:=1 to 80 do res:=res+' ';
  pos:=1;
  ch:=#0;
  while (ch<>#26) do
  begin
  read(ch);
  if ch=#26 then break;
  if not (ch in ks) then continue;

  if ch='>' then
   begin
    if pos=80 then pos:=1;
   end
  else
  if ch='<' then
   begin
    if pos<>1 then dec(pos);
   end
  else
  if pos = 80 then
  begin
   res[pos]:=ch;
   pos:=1;
  end
  else
  begin
   res[pos]:=ch;
   inc(pos);
  end

  end;
  Writeln(res);
end.

Please, help!

program p1094;
const
   ks : set of char = ['>','<','a'..'z','A'..'Z','0'..'9',';',':','-
','!','?','.',',',' '];
var
  ch : char;
  pos : byte;
  res : string[80];
begin
  res:='';
  for pos:=1 to 80 do res:=res+' ';
  pos:=1;
  ch:=#0;
  while (ch<>#26) do
  begin
  read(ch);
  if ch=#26 then break;
  if not (ch in ks) then continue;

  if ch='>' then
   begin
    if pos=80 then pos:=1
    else inc(pos);
   end
  else
  if ch='<' then
   begin
    if pos<>1 then dec(pos);
   end
  else
  if pos = 80 then
  begin
   res[pos]:=ch;
   pos:=1;
  end
  else
  begin
   res[pos]:=ch;
   inc(pos);
  end

  end;
  Writeln(res);
end.