program dezastru;
var f,g:text;
n,i,k,j:integer;
a:array[1..25] of real;
x1:array[1..25,1..25] of real;
prob:real;
begin
  assign(f,'dezastru.in'); assign(g,'dezastru.out');
  reset(f); rewrite(g);
  read(f,n,k);
  for i:=1 to n do read(f,a[i]);
  prob:=0;
  if k=1 then
    for i:=1 to n do
    prob:=prob+a[i]/n;
  close(f); close(g);
end.