#include <bits/stdc++.h>

#define fst(t) std::get<0>(t)
#define snd(t) std::get<1>(t)
#define thd(t) std::get<2>(t)
#define unless(p) if(!(p))
#define until(p) while(!(p))

using ll = std::int64_t;
using P = std::tuple<int,int>;

int N;
std::vector<int> G[100100];
int d[100100];

void dfs(int v, int p, int c){
    d[v] = c;

    for(int w : G[v]){
        if(w == p){
            continue;
        }
        
        if(d[w] == -1){
            dfs(w, v, c + 1);
        }
    }
}

int main(){
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    std::cin >> N;

    for(int i=0;i<N-1;++i){
        int a, b;
        std::cin >> a >> b;

        G[a].emplace_back(b);
        G[b].emplace_back(a);
    }

    memset(d, -1, sizeof(d));
    dfs(1, -1, 0);
    int v = std::max_element(d + 1, d + 1 + N) - d;
    memset(d, -1, sizeof(d));
    dfs(v, -1, 0);

    int mn = (N - 1) - *std::max_element(d + 1, d + 1 + N);
    std::cout << mn << std::endl;
}