var p,cnt0,cnt5,i,x,q:integer;
    f,g:text;
    ok:boolean;
begin
assign (f,'fact.in');
assign (g,'fact.out');
reset (f);
rewrite (g);
read (f,p);
cnt0:=p;
x:=0;
ok:=false;
cnt5:=0;
if p<>0 then
while not(ok) do
      begin
       x:=x+5;
       q:=x;
       while q>1 do
         begin
          if q mod 5=0 then
          begin
          cnt5:=cnt5+1;
          q:=q div 5;
          end
          else
          break;
       if cnt5=cnt0 then
          begin
          ok:=true;
          writeln (g,x);
          end;
       if cnt5>cnt0 then
          begin
           ok:=true;
           writeln (g,'-1');
          end;
         end;
      end
else
writeln (g,'1');
close (f);
close (g);
end.