#include <fstream>
#include <vector>

constexpr int kMaxN = 100000;
constexpr int kNotVisited = -1;

int n, m;
std::vector<int> edges[kMaxN+1];
int depth[kMaxN+1], deepest_node = 1;

void dfs(int x) {
    if(depth[x] > depth[deepest_node]) deepest_node = x;
    for(int y : edges[x]) {
        if(depth[y] == kNotVisited) {
            depth[y] = depth[x]+1;
            dfs(y);
        }
    }
}

int main()
{
    std::ifstream in("darb.in");
    std::ofstream out("darb.out");
    in>>n;
    m = n-1;
    for(int i = 1; i <= n; ++i) depth[i] = kNotVisited;
    for(int x, y, i = 1; i <= m; ++i) {
        in>>x>>y;
        edges[x].push_back(y);
        edges[y].push_back(x);
    }
    deepest_node = 1;
    depth[1] = 1;
    dfs(1);
    for(int i = 1; i <= n; ++i) depth[i] = kNotVisited;
    depth[deepest_node] = 1;
    dfs(deepest_node);
    out<<depth[deepest_node]<<'\n';
    return 0;
}