{
ZADATAK: proizvod
JEZIK: pascal
}
program proizvod;
type
 niz=array[1..10000] of integer;
var
i,j,l,m,n,ostatak,p:integer;
a:niz;
r,b,c: array[1..10] of integer;
k:char;
f:text;
procedure razmeni(var a,b:integer);
var pom:integer;
 Begin
  pom:=a;
  a:=b;
  b:=pom;
 End;

procedure QS(levi,desni:integer; var a:niz);
 var i,j:integer;
     d:integer;
 Begin
   if (levi<desni) then
     Begin
       i:=levi;
       j:=desni;
       d:=a[desni];
        repeat
         while (a[i]<d) do i:=i+1;
         while (a[j]>=d) do j:=j-1;
         if i<j then razmeni(a[i],a[j]);
        until i>=j;
       razmeni(a[i],a[desni]);
       QS(levi,i-1,a);
       QS(i+1,desni,a);
     End;
 End;



Begin
assign(f,'proizvod.in');
reset(f);
readln(f,n,m);
for i:=1 to n  do
 Begin
  read(f,k);
  a[i]:=ord(k)-ord('0');
 End;
QS(1,n,a);
close(f);


if (n mod 2)=0 then
  Begin
    b[1]:=a[n];
    c[1]:=a[n-1];
    i:=2;
    l:=1;
     while i<=(n-2) do
      Begin
       l:=l+1;
       c[l]:=a[n-i];
       b[l]:=a[n-i-1];
       i:=i+2;
      end;
   if 2*l>=m then
   begin
    for i:=1 to m do
      Begin
        ostatak:=0;
        for j:=i to m do
          Begin
          p:=b[l-i+1]*c[l-j+i]+ostatak;
          r[j]:=(r[j]+p) mod 10;
          ostatak:=p div 10;
          End;
      End;

   End
      else
        for i:=1 to l do
         Begin
           ostatak:=0;
           for j:=i to l do
            Begin
             p:=b[l-i+1]*c[l-j+i]+ostatak;
             r[j]:=(r[j]+p) mod 10;
             ostatak:=p div 10;
            End;
         End;
   End
 else
   Begin
    b[1]:=a[n];
    c[1]:=a[n-1];
    i:=2;
    l:=1;
     while i<n-1 do
      Begin
       l:=l+1;
       c[l]:=a[n-i];
       b[l]:=a[n-i-1];
       i:=i+2;
      end;
    b[n]:=a[1];
   if 2*l>=m then
   begin
    for i:=1 to m do
      Begin
        ostatak:=0;
        for j:=i to m do
          Begin
          p:=b[l-i+1]*c[l-j+i]+ostatak;
          r[j]:=(r[j]+p) mod 10;
          ostatak:=p div 10;
          End;
      End;

   End
      else
        for i:=1 to l do
         Begin
           ostatak:=0;
           for j:=i to l do
            Begin
             p:=b[l-i+1]*c[l-j+i]+ostatak;
             r[j]:=(r[j]+p) mod 10;
             ostatak:=p div 10;
            End;
         End;



  End;
assign(f,'proizvod.out');
rewrite(f);
for i:=m downto 1 do
  write(f,r[i]);
close(f);



End.


