program juxingfenge;
var
  n,m,i,t:longint;
  a:array[1..4000]of longint;
procedure sort(l,r: longint);
      var
         i,j,x,y: longint;
      begin
         i:=l;
         j:=r;
         x:=a[(l+r) div 2];
         repeat
           while a[i]<x do
            inc(i);
           while x<a[j] do
            dec(j);
           if not(i>j) then
             begin
                y:=a[i];
                a[i]:=a[j];
                a[j]:=y;
                inc(i);
                j:=j-1;
             end;
         until i>j;
         if l<j then
           sort(l,j);
         if i<r then
           sort(i,r);
      end;

begin
  assign (input,'cut.in');
  reset (input);
  assign (output,'cut.out');
  rewrite (output);
  readln (n,m);
  for i:=1 to n+m-2 do
    readln (a[i]);
  sort(1,n+m-2);
  for i:=n+m-2 downto 1 do
    t:=t+a[i]*i;
  writeln (t);
  close (input);
  close (output)
end.