var f1,f2:text;
    c,cz,s,p:longint;
begin
assign(f1,'fact.in');
assign(f2,'fact.out');
reset(f1);
rewrite(f2);
readln(f1,p);
if p=0 then begin
             writeln(f2,1);
             close(f1);
             close(f2);
             halt;
            end;
s:=0;cz:=0;
repeat
 s:=s+5;
 c:=s;
 while (c mod 5=0) and (c>=1) do
  begin
   cz:=cz+1;
   c:=c div 5;
  end;
until cz>=p;
if cz=p then writeln(f2,s)
        else writeln(f2,-1);
close(f1);
close(f2);
end.