static bool isNormalQuoted(S s) {
  int l = l(s);
  if (!(l >= 2 && s.charAt(0) == '"' && lastChar(s) == '"')) false;
  int j = 1;
  while (j < l)
    if (s.charAt(j) == '"')
      ret j == l-1;
    else if (s.charAt(j) == '\\' && j+1 < l)
      j += 2;
    else
      ++j;
  false;
}