program fractii;
var n,x,a,i:integer;
    f,g:text;
begin
 assign(f,'fractii.in');
 reset(f);
 assign(g,'fractii.out');
 rewrite(g);
 readln(f,n);
 a:=7;
 x:=7;
 {n:=3, a:=7, x:=7
  n:=4, a:=7, x:=7*2-3 x:=11}
        for i := 3 to n do
        x:=x*2-3;
 writeln(g,x);
 close(f);
 close(g);
end.