Program factoriale;
var
f,g:text;
n,i,j,k,a:byte;
m,p,l:longint;
begin
  assign(f,'factoriale.in');reset(f);
  assign(g,'factoriale.out');rewrite(g);
  readln(f,n,k);
  m:=1;
  for i:=1 to n do
   begin
    read(f,a);
    for j:=1 to a do
      m:=m*j;
   end;
  p:=1;
  j:=0;
  while(p mod m<>0) do
   begin
    p:=1;
    inc(j);
    for i:=1 to k do
      p:=p*j;
   end;
  l:=p div m;
  writeln(g,l);
  close(f);
  close(g);
end.