//interactive

struct S{
	unsigned a;
	int j[18];
};

S s[80000];
int dv[18][80000];
int dn[18];

void add(ll i){
	rep(z,1,18){
		if(s[i].a&1<<z-1){
			dv[z][dn[z]]=i;
			s[i].j[z]=dn[z];
			dn[z]+=1;
		}
	}
}

void del(ll i){
	rep(z,1,18){
		if(s[i].a&1<<z-1){
			dn[z]-=1;
			dv[z][s[i].j[z]]=dv[z][dn[z]];
		}
	}
}

{
	ll@n;
	unsigned x=0;
	rep(i,n){
		unsigned@a;
		x^=a;
		s[i].a=a;
		add(i);
	}
	if(x==0){
		wt(0);
		goto opp_turn;
	}
	wt(1);

	my_turn:;
	{
		ll z=32-__builtin_clz(x);
		ll i=dv[z][dn[z]-1];
		del(i);
		unsigned b=x^s[i].a;
		wt(i+1,s[i].a-b);
		s[i].a=b;
		add(i);
	}
	{
		ll@a;
		if(a<0){
			exit(0);
		}
	}

	opp_turn:;
	{
		ll@--i;
		unsigned@k;
		del(i);
		x=s[i].a;
		s[i].a-=k;
		x^=s[i].a;
		add(i);
	}
	{
		ll@a;
		if(a<0){
			exit(0);
		}
	}

static int dbg_turn=0;
if(++dbg_turn==100){
exit(3);
}

	goto my_turn;
}