begin
comment calculate length of the string;
	string (40) s;
	string (1) sp;
	integer i, ii, n, len;
	
	n := 40;
	sp := " ";
	len := 0;
	s := "123abcd456";
	
	for i := 0 until (n-1) do
	begin
		ii := 39 - i;
		if s(ii|1)  = sp then len := len +1
		else goto finish;
	end;
finish:
	len := n-len;
	write(len);
end.