var P,N,Z,p5,cn:longint;
begin
  assign(input,'fact.in'); reset(input);
  assign(output,'fact.out'); rewrite(output);
  readln(p);
  if p=0 then writeln(1)
  else begin
    n:=4*P; n:=n-n mod 5;
    z:=0; p5:=5;
    while n>=p5 do begin
      z:=z+n div p5;
      p5:=p5*5;
    end;
    while z<p do begin
      inc(n,5); cn:=n;
      while cn mod 5=0 do begin inc(z); cn:=cn div 5;end;
    end;
    if z=p then writeln(n)
    else writeln(-1);
  end;
  close(input); close(output);
end.