var n,s,i,u:longint;
begin
assign(input,'cifra.in'); reset(input);
assign(output,'cifra.out'); rewrite(output);
while not eof do begin
        readln(n);

s:=0;
for i:=1 to n do begin
    if i mod 4=1 then u:=i mod 10
                 else if i mod 4=2 then u:=(i*i) mod 10
                                   else if i mod 4=3 then u:=(i*i*i) mod 10
                                                     else u:=(i*i*i*i) mod 10;
    s:=s+u;
    end;
s:=s mod 10;
writeln(s);
end;
close(input);
close(output);
end.