function trim(s) {
  while (s.length>0 && (s[0]==' '||s[0]=='\n')) s=s.substring(1, s.length);
  while (s.length>0 && (s[s.length-1]==' '||s[s.length-1]=='\n')) s=s.substring(0, s.length-1);
  return s; 
}