#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (int)(n); i++)

using namespace std;
using LL = long long;
using P = pair<int,int>;
using vv = vector<vector<int>>;
const int INF = (int)1e9;
const LL LINF = (LL)1e18;
const int Max_N = (int)2e5;

class UnionFind {
public:
	vector <long long> par;
	vector <long long> siz;

	UnionFind(long long sz_): par(sz_), siz(sz_, (long long)1) {
		for (long long i = 0; i < sz_; ++i) par[i] = i;
	}
	void init(long long sz_) {
		par.resize(sz_);
		siz.assign(sz_, (long long)1);
		for (long long i = 0; i < sz_; ++i) par[i] = i;
	}

	long long root(long long x) {
		while (par[x] != x) {
			x = par[x] = par[par[x]];
		}
		return x;
	}

	bool unite(long long x, long long y) {
		x = root(x);
		y = root(y);
		if (x == y) return false;
		if (siz[x] < siz[y]) swap(x, y);
		siz[x] += siz[y];
		par[y] = x;
		return true;
	}

	bool same(long long x, long long y) {
		return root(x) == root(y);
	}

	long long size(long long x) {
		return siz[root(x)];
	}
};

vv G;
int depth = 0, f = 0;
void dfs(int n, int d = 0, int par = -1){
	if(d >= depth){
		depth = d;
		f = n;
	}
	for(auto v : G[n]){
		if(v == par) continue;
		dfs(v, d + 1, n);
	}
}

int main(){
	int N;
	cin >> N;
	assert(2 <= N and N <= Max_N);
	UnionFind uf(N);
	G.resize(N);
	rep(i,N-1){
		int a, b;
		cin >> a >> b;
		assert(1 <= a and a < b and b <= N);
		a--; b--;
		G[a].emplace_back(b);
		G[b].emplace_back(a);
		uf.unite(a, b);
	}
	int r = 0;
	rep(i,N) if(uf.root(i) == i) r++;
	assert(r == 1);
	dfs(0);
	dfs(f);
	cout << (N - 1) * 2 - depth << endl;

	return 0;
}