Program p3;
Var n,k1,k2,k3,k4,s,i:longint;
    f,ff:text;
Begin
  assign(f,'koba.in');
  reset(f);
  assign(ff,'koba.out');
  rewrite(ff);
  readln(f,n,k1,k2,k3);
  k1:=k1 mod 10;
  k2:=k2 mod 10;
  k3:=k3 mod 10;
  s:=k1+k2+k3;
  for i:=4 to n do
     begin
      k4:=(k3+k1*k2) mod 10;
      k1:=k2;
      k2:=k3;
      k3:=k4;
      s:=s+k4;
     end;
  Writeln(ff,s);
  close(f);
  close(ff);
End.