var f:text;
    p,r,fac,facc:longint;

begin
assign(f ,'fact.in');
reset(f);
read(f,p);
close(f);
r:=0;
fac:=1;
while r<p do
 begin
  r:=r+fac;
  fac:=fac*5;
 end;
assign(f ,'fact.out');
rewrite(f);
if r=p then
write(f,fac)
 else
begin
 while r>p do
  Begin
   facc:=fac;
   while facc mod 5=0 do
        begin
         facc:=facc div 5;
         r:=r-1;
        end;
   fac:=fac-5;
  End;
 if r=p then
  write(f,fac)
   else
  write(f,'-1');
end;
close(f);
end.