var
  t: real;
  n, k, i,j: integer;
  a:array [1..101] of integer;

begin
  readln(n);
  for i := 1 to n do
  begin
    read(a[i]);
  end;
  for i:=1 to n do
  begin
    for j:=1 to n do
    begin
    if a[i]<a[j] then
    begin
      swap(a[i],a[j]);
    end;
    end;
  end;

  for i:=1 to (n div 2)+1 do
  begin
    t:=t+((a[i] div 2)+1);
  end;

  write(t);
end.