#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0;i<((int)(n));i++)
#define reg(i,a,b) for(int i = ((int)(a));i<=((int)(b));i++)
#define irep(i,n) for(int i = ((int)(n)-1);i>=0;i--)
#define ireg(i,a,b) for(int i = ((int)(b));i>=((int)(a));i--)
typedef long long ll;
typedef pair<ll, ll> mp;
ll mod = 1e9+7;
//LLONG_MIN

/*
やばい
*/

ll n,visit[2][100010]={},used[100010]={},d[2][100010],inf=1e18,ans=0;
vector<ll> v[100010];
queue<ll> Q;

void reset(ll p){
	queue<ll> Q;
	Q.push(p);
	d[0][p]=inf;
	d[1][p]=inf;
	while(!Q.empty()){
		p=Q.front();Q.pop();
		for(ll q:v[p]){
			if(used[q]==0 && d[0][q]!=inf){
				d[0][q]=inf;
				d[1][q]=inf;
				Q.push(q);
			}
		}
	}
	// cout<<p<<" reset"<<endl;
}

void f(ll p,ll m){
	queue<ll> Q;
	Q.push(p);
	d[m][p]=0;
	while(!Q.empty()){
		p=Q.front();Q.pop();
		for(ll q:v[p]){
			if(used[q]==0 && d[m][q]>d[m][p]+1){
				d[m][q]=d[m][p]+1;
				Q.push(q);
			}
		}
	}
	// cout<<p<<" dist"<<endl;
}

ll g(ll p,ll m){
	ll largest=p;
	queue<ll> Q;
	Q.push(p);
	while(!Q.empty()){
		p=Q.front();Q.pop();
		for(ll q:v[p]){
			if(used[q]==0){
				if(d[m][largest]<d[m][q]){
					largest=q;
					Q.push(q);
				}
			}
		}
	}
	// cout<<p<<" largest"<<endl;
	return largest;
}

void h(ll p){
	// reg(i,1,n){
	// 	cout<<i<<": "<<d[0][i]<<","<<d[1][i]<<endl;
	// }
	queue<ll> R;
	R.push(p);
	while(!R.empty()){
		p=R.front();R.pop();
		used[p]=1;
		// cout<<p<<endl;
		for(ll q:v[p]){
			if(used[q]==0){
				if(d[0][p]+d[1][p]==d[0][q]+d[1][q]){
					R.push(q);
				}else{
					//それ以外の点
					Q.push(q);
					ans++;
				}
			}
		}
	}
	// cout<<p<<" used"<<endl;
}

int main(void){
	cin>>n;
	rep(i,n-1){
		ll a,b;
		cin>>a>>b;
		v[a].push_back(b);
		v[b].push_back(a);
	}
	ll p=1;
	Q.push(1);
	while(!Q.empty()){
		ll p=Q.front();Q.pop();
		reset(p);
		f(p,0);
		ll q=g(p,0);//最遠点1
		reset(q);
		f(q,0);
		ll r=g(q,0);//最遠点2
		f(r,1);
		h(q);
		// cout<<ans<<endl;
	}
	cout<<ans<<endl;
	return 0;
}