var n,k,i,p,a:longint;
    f,g:text;
    ok:boolean;
begin
assign(f,'fact.in'); reset(f);
assign(g,'fact.out'); rewrite(g);
read(f,p);
ok:=true;
i:=0; k:=0;
while k<p do begin
  i:=i+5;
  a:=i;
  while (a mod 5=0) and (a<>0) do begin
    k:=k+1;
    if k=p then break;
    a:=a div 5;
  end;
end;
if p=0 then write(g,'1')
       else write(g,i);
close(g);
end.