var p,x,nr,k:longint;
    f,g:text;
begin
assign(f,'fact.in');reset(f);
assign(g,'fact.out');rewrite(g);
readln(f,p);
close(f);
x:=0;
nr:=0;
while x<p do
  begin
    nr:=nr+5;
    k:=nr;
    while k mod 5 =0 do
      begin
        x:=x+1;
        k:=k div 5;
      end;
  end;

if x<>p then
  writeln(g,'-1')
else begin
  if p=0 then
     nr:=1;
  writeln(g,nr);
end;
close(g);
end.