function dinumber(in_st)
 {
  a = in_st.split(" ");
  var addsqrs = 0;
  var added = 0;
  var cur_val = 0;
  for (i=0; i < a.length; ++i)
   { cur_val = parseFloat(a[i])
     addsqrs = addsqrs + cur_val * cur_val
     added = added + cur_val; }
  result = (added * added) / addsqrs;
  return result
 }