program koba;
var f,g:text;
    n,t1,t2,t3,aux,s,i,t:longint;
begin
assign(f,'koba.in');
assign(g,'koba.out');
reset(f);
rewrite(g);
read(f,n,t1,t2,t3);
t1:=t1 mod 10;
t2:=t2 mod 10;
t3:=t3 mod 10;
s:=t1+T2+T3;
for i:=4 to n do
  begin
    t:=t3+(t2*t1);
    t:=t mod 10;
    aux:=t3;
    t3:=t;
    t1:=t2;
    t2:=aux;
    s:=s+t;
  end;
write(g,s);
close(f);
close(g);
end.