#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define fi first
#define se second
#define FOR(i,n) for(int i = 0;i<n;i++)
#define rep(i,s,n) for(int i = s;i<n;i++)
#define rrep(i,s,n) for(int i = (n)-1;i>=(s);i--)
#define all(v) (v).begin(),(v).end()
#define chmin(a,b) a=min((a),(b))
#define chmax(a,b) a=max((a),(b))
#define endl '\n'
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0)
typedef long long ll;
typedef pair<int,int>pint;
typedef vector<int>vint;
typedef vector<pint>vpint;
const ll MOD=1000000007,INF=1ll<<60;
typedef vector<vint>vvint;

int N;
vint g[100010];
int dist[100010];

void dfs(int now,int par){
    for(auto e:g[now]){
        if(e==par)continue;
        dist[e]=dist[now]+1;
        dfs(e,now);
    }
}

signed main() {
    IOS();
    cin>>N;
    rep(i,0,N-1){
        int a,b;
        cin>>a>>b;
        a--;b--;
        g[a].pb(b);
        g[b].pb(a);
    }
    
    dfs(0,-1);
    int t=-1,ma;
    rep(i,0,N){
        if(t<dist[i]){
            t=dist[i];
            ma=i;
        }
    }
    rep(i,0,100010)dist[i]=0;
    dfs(ma,-1);
    t=-1,ma;
    rep(i,0,N){
        if(t<dist[i]){
            t=dist[i];
            ma=i;
        }
    }
    cout<<N-1-t<<endl;
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    return 0;
}