#include <bits/stdc++.h>
#define nmax 100001

using namespace std;

class InParser {
private:
	FILE *fin;
	char *buff;
	int sp;

	char read_ch() {
		++sp;
		if (sp == 4096) {
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}

public:
	InParser(const char* nume) {
		fin = fopen(nume, "r");
		buff = new char[4096]();
		sp = 4095;
	}

	InParser& operator >> (int &n) {
		char c;
		while (!isdigit(c = read_ch()) && c != '-');
		int sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}

	InParser& operator >> (long long &n) {
		char c;
		n = 0;
		while (!isdigit(c = read_ch()) && c != '-');
		long long sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}
};

InParser fin ("darb.in");
ofstream fout ("darb.out");

int n, x, y, D, last, dist[nmax];
bool viz[nmax];
vector < int > G[nmax];
queue < int > Q;

void Read () {
    fin >> n;
    for (int i = 1; i < n; i ++) {
        fin >> x >> y;
        G[x].emplace_back (y);
        G[y].emplace_back (x);
    }
}

void BFS (int start) {
    Q.push (start);
    dist[start] = 1, viz[start] = 1;
    while (!Q.empty()) {
        int x = Q.front();
        Q.pop();
        for (size_t i = 0; i < G[x].size(); i ++)
        if (!viz[G[x][i]]) {
            Q.push (G[x][i]);
            dist[G[x][i]] = dist[x] + 1;
            viz[G[x][i]] = 1;
            D = dist[G[x][i]];
            last = G[x][i];
        }
    }
}

int main() {
    ios_base::sync_with_stdio (false);
    fout.tie (0);
    Read ();
    BFS (1);
    memset (dist, 0, sizeof(dist));
    memset (viz, 0, sizeof(viz));
    BFS (last);
    fout << D;
    fout.close();
    return 0;
}