var n,k,i,x,max,l,j,nr,xr,u:longint;
    v:array[1..100] of integer;
    f,g:text;
begin
     assign(f,'factoriale.in');
     assign(g,'factoriale.out');
     reset(f);
     rewrite(g);
     read(f,n,k);
     j:=2;
     l:=0;
     nr:=1;
     for i:=1 to n do begin
                   read(f,x);
                   for u:=2 to x do begin
                        xr:=u;
                   while xr>1 do begin
                         if xr mod j=0 then begin
                                           xr:=xr div j;
                                           inc(l);
                                           end
                                      else begin
                                           v[j]:=v[j]+l;
                                           l:=0;
                                           inc(j);
                                           end;
                                end;
      v[j]:=v[j]+l;
      l:=0;
      j:=2;
      end;
      end;
      for i:=2 to 97 do
              if (v[i]>0) and (v[i]<k) then
                        for j:=1 to k-v[i] do
                               nr:=nr*i;
     write(g,nr);
     close(f);
     close(g);
end.