#include <bits/stdc++.h>
#define ull unsigned long long
#define FILES freopen("darb.in","r",stdin);\
              freopen("darb.out","w",stdout);
#define CMAX 1000000
#define fastio std::ios_base::sync_with_stdio(NULL),cin.tie(NULL),cout.tie(NULL);
#define mp make_pair
#define INF 999999999999999
#define mod 1000000007
#define ll long long
#define MAX 100000
#define SMAX 500000
#define pb push_back
#define add emplace_back
#define void inline void
using namespace std;
int n,fr[MAX+5],ans,z;
bool ok[MAX+5];
pair<int,int> dp[MAX+5];
vector<int> v[MAX+5];
void Dfs(int x,int r)
{
    ok[x] = 1,fr[x] = r;
    for(auto i : v[x]) if(!ok[i]) Dfs(i,r+1);
}
int main()
{
    fastio
    FILES
    cin >> n;
    for(int i = 1;i < n; ++i)
    {
        int a,b;
        cin >> a >> b;
        v[a].add(b),v[b].add(a);
    }
    Dfs(1,0);
    int best = -1,pz = -1;
    for(int i = 1;i <= n; ++i) if(fr[i] > best) best = fr[i],pz = i;
    memset(ok,false,sizeof(ok));
    Dfs(pz,0);
    best = -1;
    for(int i = 1;i <= n; ++i)
    {
        if(pz == i) continue;
        if(fr[i] > best) best = fr[i];
    }
    cout << best + 1;
}