#include<cstdio>
#include<string>
#include<bitset>
#include<vector>

using namespace std;

#ifdef HOME
const string inputFile = "input.txt";
const string outputFile = "output.txt";
#else
const string problemName = "darb";
const string inputFile = problemName + ".in";
const string outputFile = problemName + ".out";
#endif

const int NMAX = 100000 + 5;

int N, leaf;
vector<int> V[NMAX];
bitset<NMAX> viz;
int D[NMAX];

void dfs(int x) {
    viz[x] = 1;

    for(auto y : V[x])
        if(!viz[y]) {
            D[y] = D[x] + 1;
            dfs(y);
        }

    if(D[x] > D[leaf])
        leaf = x;
}

int main() {
    int i, x, y;

    freopen(inputFile.c_str(), "r", stdin);
    freopen(outputFile.c_str(), "w", stdout);

    scanf("%d", &N);

    for(i = 1; i <= N - 1; i++) {
        scanf("%d%d", &x, &y);
        V[x].push_back(y);
        V[y].push_back(x);
    }

    D[1] = 1;

    dfs(1);

    viz = 0;
    D[leaf] = 1;

    dfs(leaf);

    printf("%d\n", D[leaf]);

    return 0;
}