var p,n,c,k:longint;
    f,g:text;
begin
assign(f,'fact.in');
reset(f);
assign(g,'fact.out');
rewrite(g);
read(f,p);
repeat
  inc(n);
  k:=n;
  while k mod 5=0 do
    begin
      k:=k div 5;
      inc(c);
    end;
until c=p;
write(g,n);
close(f);
close(g);
end.