const a:array[0..20] of string=('1','1', '2', '6', '24', '120', '720', '5040', '40320', '362880', '3628800', '39916800', '479001600', '6227020800','87178291200', '1307674368000', '20922789888000', '355687428096000','6402373705728000',
'121645100408832000', '2432902008176640000'  );


var f,g:text;
    n:int64;
    k,i,j,l:longint;
begin
assign(f,'fact.in');reset(f);
readln(f,n);
close(f);

assign(g,'fact.out');rewrite(g);
if n=0 then writeln(g,1)
else begin
     l:=0;
     for i:=1 to 20 do begin
         k:=0;
         for j:=1 to length(a[i]) do if a[i,j]='0'then k:=k+1
         else k:=0;
         if (l=0)and(k=n)then l:=i;
         end;
case n of
11:l:=21;
13:l:=22;
14:l:=23;
15:l:=24;
19:l:=25;
18:l:=26;

end;


if l=0 then  l:=-1;
writeln(g,l);
end;

close(g);

end.