var p : longint;
    n, m : longint;
    t : text;
begin
assign(t,'fact.in');
reset(t);
readln(t,p);
if p=0 then n:=1;
while p>0 do begin inc(n,5);
                   m:=n;
                   while m mod 5=0 do begin dec(p);
                                            m:=m div 5;
                                      end;
             end;
close(t);
assign(t,'fact.out');
rewrite(t);
writeln(t,n);
close(t);
end.