program fact;
{$APPTYPE CONSOLE}
uses
  SysUtils;
var n2,n5,nn,i,p,n,aux:longint;
    fin,fout:text;
{*---------MAIN-----------------*}
begin
  assign(fin,'fact.in');
  assign(fout,'fact.out');
  reset(fin);
  rewrite(fout);
  readln(fin,p);
  n:=0;
  if p > 9 then
    begin
      aux:=p div 10;
      n:=5;
      for i:=1 to aux do
        n:=n+40;
    end;
  if p mod 10 > 0 then for i:=1 to p mod 10  do
                          n:=n+5;
      n2:=0;
      n5:=0;
  for i:=2 to n do
    begin
      aux:=i;
      while aux mod 2 = 0 do
        begin
          inc(n2);
          aux := aux div 2;
        end;
      while aux mod 5 = 0 do
        begin
          inc(n5);
          aux := aux div 5;
        end;
    end;
      nn:=n5;
      if n2 < n5 then nn:=n2;
      if nn = p then
        begin
          writeln(fout,n);
        end;
      if nn <>p then
        begin
          writeln(fout,-1);
        end;
  close(fout);
end.