program sum;
{$APPTYPE CONSOLE}
uses SysUtils;
var x, s: real;
var i: integer;
begin
    s := 0;
    i := 0;
    write('Please Enter x[', i:3, ']: ');
    readln(x);
    while 0 <= x do begin
        s := s + x;
        i := i + 1;
        write('Please Enter x[', i:3, ']: ');
        readln(x);
    end;
    writeln('sum =', s:8:3);
    writeln('average =', (s/i):8:3);
    readln
end.