program f_soma;

function soma: integer;
var
   v, s : integer;
begin
   s := 0;   
   repeat
      readln(v);
      if (v <> -1) then
	 s := s + v;
   until v = -1;
   soma := s;
end;  

var
   res : integer;
begin
   res := soma;
   writeln('O valor da soma é: ', res);
end.