ll n,r,u[2d5],w[2d5];
vector<ll>v[2d5];

ll f(ll j){
	ll a=w[j]=1;
	rep(i,v[j].size()){
		ll x=v[j][i];
		if(!w[x]&&f(x))a=0;
	}
	r+=a;
	return a;
}

{
	rd(n,u(n*2-2));
	v[u[0..n*2-3]].push_back(u[(0..)^1]);
	f(1);
	wt(r);
}