/* merge sort in js */
function sort(a) {
  var mid = a.length>>1;
  if (mid==0) return a;
  var less = sort(a.slice(0,mid));
  var more = sort(a.slice(mid));
  var merged = [];
  do {
    if (more[0] < less[0]) { var t=less; less=more; more=t; }
    merged.push(less.shift());
  } while (less.length > 0);
  return merged.concat(more);
}