var j,k,z,d,s,c,i:integer;n:int64;
    f1,f2:text;
    b:boolean;
begin
    Assign(f1,'cifra.in');reset(f1);
    Assign(f2,'cifra.out');rewrite(f2);
readln(f1,n);z:=0;
        For i:=1 to n do begin
            c:=i mod 4;If c=0 then c:=4;d:=1;
            For k:=1 to c do begin
                d:=d*(i mod 10)mod 10;
            end;
            s:=(s+d)mod 10;
        end;
writeln(f2,s);
close(f1);
close(f2);
end.