program faktor;
var p,n,db,x:longint;
    f:text;
begin
     assign(f,'fact.in'); reset(f);
     readln(f,p);
     close(f);
     if p mod 6=5 then n:=-1 else begin
     n:=0; db:=0;
     repeat
           inc(n,5);
           inc(db);
           x:=n;
           while (x div 5) mod 5=0 do begin inc(db);
                                            x:=x div 5;
                                      end;
     until db=p;   end;
     assign(f,'fact.out'); rewrite(f);
     write(f,n);
     close(f);
end.