!752

p {
  makeBot("PN Calc.");
}

answer {
  L<S> tok = javaTok(s);
  if (eq(get(tok, 1), "+")) {
    BigInteger b = bigint(0);
    for (int i = 3; i < l(tok); i += 2)
      b = b.add(bigint(tok.get(i)));
    ret str(b);
  }
}