var c,p,n,i,q:longint;
    f,g:text;
    ok:boolean;
begin
assign(f,'fact.in');
assign(g,'fact.out');
reset(f);
rewrite(g);
readln(f,p);
i:=p div 25;
n:=5*p-5*(p div 5);
q:=5*(p-1)-5*((p-1) div 5);
if n<>q then
   writeln(g,n)
   else writeln(g,-1);
close(f);
close(g);
end.