#include <cstdio>
#include <vector>
using namespace std;

const int nmx = 100002;

int n,nod_d,dmax = -1;
vector <int> g[nmx];

void input(){
    scanf("%d", &n);
    int nod1,nod2;
    for(int i = 1; i < n; ++i){
        scanf("%d %d", &nod1, &nod2);
        g[nod1].push_back(nod2);
        g[nod2].push_back(nod1);
    }
}

void dfs(int tata, int nod, int dist){
    if(dist > dmax){
        dmax = dist;
        nod_d = nod;
    }
    for(vector<int>::iterator it = g[nod].begin(); it != g[nod].end(); ++it)
        if(*it != tata)
            dfs(nod,*it,dist+1);
}

int main(){
    freopen("darb.in", "r", stdin);
    freopen("darb.out", "w", stdout);
    input();
    dfs(0,1,1);
    dfs(0,11,1);
    printf("%d", dmax);
    return 0;
}